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The Extrapolation Chamber: Are these second-half breakout hitters for real?

I have to admit, this article is nearly as much about fun and nostalgia as it is about analysis. I think back to my younger days when a player would have a huge week or two to start the season, and how we’d try to project those numbers forward. This was before the days of advanced stats and even finding a player’s minor league stats wasn’t easy. So when Tuffy Rhodes hits three bombs on Opening Day, we realized he wasn’t gonna hit 450 homers on the year, but 40 would be doable right? Nowadays we have a lot more data to work with and we know a lot more about sample size and regression. Still, it doesn’t stop us from getting excited when we look at players who start out the season with a hot month of April, or at young players who come up and dominate MLB pitching for a couple of months late in the season. Today we’re gonna take a look at a few of the breakout hitters from the second half of the 2018 season and try to figure out if they’re for real… And we’ll also extrapolate those second-half numbers over a full season and dream about what could be… And please don’t tell me that extrapolation is not accurate for predicting future performance. I know that. Loosen up your jock strap and have some fun!

If you’re like us, you can’t wait until spring to get the 2019 fantasy baseball season started. Well, you don’t have to. Leagues are already forming at, so head on over and get your league started today.

Putting 2018 Breakout Hitters Through the Extrapolation Chamber

The basic idea here is that we take the numbers from some of the top breakout hitters of 2018, and extrapolate those numbers out to 650 plate appearances. In most cases, we won’t even pretend that these players can even come close to their extrapolated numbers. If it always worked, Matt Olson would have hit like 120 homers last year. The extrapolation is the fun part.

Then we have to deal with reality and try to figure out what to truly expect from them in 2019. That’s the hard part. Even hardened fantasy veterans like myself get excited when we see the crooked numbers in these extrapolated stat lines. I’m gonna do my best to remain based in reality and remember how Tuffy Rhodes let me down.

Ronald Acuna and Juan Soto

Technically we can’t consider these two young studs second-half breakouts as they played more than most of the other names we’ll talk about in the coming paragraphs. Still, I thought it would be fun to see what their 2018 numbers looked like for a full season. And no matter how much they look like stars for the next decade, we have to at least question whether Acuna and Soto can make adjustments as MLB pitchers undoubtedly change the way they will pitch to them.

Juan Soto, OF Washington Nationals
Juan Soto extrapolated

Listen, I’m not gonna overanalyze Soto or Acuna. There’s nothing in the peripherals of either players that screams fluke. Soto will play the entire 2019 season as a 20-year-old and if anything could improve. He controls the strikeouts (20.0 K%) and will take a walk (16.0 BB%). That advanced plate discipline means he’s gonna be golden in OBP leagues. The only concern will be how he adjusts as pitchers attack him differently.

After all, we know he destroys fastballs. Check this out from

Soto hit 14 of 25 doubles, 15 of his 22 home runs, and had a .386 AVG on fastballs in 2018, (with three more doubles and four home runs on sinkers), and hit three doubles and one of his home runs off a slider, but had just a .186 AVG on the breaking ball.

Soto seemed to adjust well in his winter tour of Japan, but it might be wise to expect something closer to his .286 second-half average than the mid-.300 barrage he put up in his first two months. Other than that there’s no reason not expect close to 30 home runs, along with 90-100 runs scored with his on-base skills. Early Fantrax ADP has him going off the board at pick 31 which is pretty fair. There may be more power or speed upside available at that point, but Soto actually has an extremely high floor for a player so young. I’m drafting with confidence in 2019.

Ronald Acuna Jr., OF, Atlanta Braves
Ronald Acuna breakout hitters

Ronald Acuna second half stats

About now you are noticing there are two different stat lines for Acuna. The first is his entire 2018 season extrapolated to 650 plate appearances. The second is his blistering hot second half after returning from a scary knee injury that cost him almost all of June. Just to give you an idea of how good he was in the second half, Acuna carried a .249 average with seven homers and two steals into the second half.

So can Acuna maintain that crazy good second half? Is he a .320 hitter with 40-homer power? Both are questionable but cannot be totally ruled out. Acuna’s 22.1 K% in the second half is actually pretty indicative of what he did in the minor leagues, so strikeouts are not going to be a huge problem. His .367 BABIP in the second half may come down a bit, but he is a fast runner and hits the ball consistently hard (44.4 Hard%). A .320 average may be asking too much, but Acuna is gonna be a .290-plus hitter unless things fall completely apart.

Initially, I thought the power may be a little more doable, but the 25.3 HR/FB% may not be repeatable. The highest mark he’d put up in his minor league career was 17.6. I can buy an increase at the Major League level, but that big? I feel good expecting 30-to-35 home runs from Acuna, but I’m not sure he’s ready to hit the 40-homer line.

I think the big question with Acuna is how much the Braves let him run. He led off for the Braves in the second half and even after the knee injury they were pretty aggressive. Does he lead off again? I drafted Acuna with the No. 8 pick in a recent mock for a fantasy magazine. If he approaches 30 stolen bases I think I’ll be very happy with that pick. Steamer has him down for 25. I could live with that as well.

I’m not sure I’ve ever been comfortable with a second-year player in the first round. I am with Ronald Acuna… If he stays healthy.

Franmil Reyes, OF, San Diego Padres
Franmil Reyes Breakout Hitter

It was a tale of two seasons for Reyes. One from May through July when he hit .221 with six homers and eight RBIs along with 42 strikeouts in 111 plate appearances and got sent back down twice; the other from Aug. 4 on when he came back with a vengeance. Upon his return, he hit .312 with nine home runs in 171  plate appearances. He also lowered his strikeout rate to a manageable 21.6%.

Much like many others, I’m sure, I dismissed Reyes after his first two showings and was a bit surprised to see just how well he hit the last few months of 2018. I came into this article a bit skeptical, but in looking through his minor league numbers, I’m not sure strikeouts are going to be as much of an issue as I initially thought. Reyes is not especially fast, so the .345 BABIP is likely to come down, but the power seems to be for real.

The Padres outfield has a lot of moving parts. A slow start could get Reyes in trouble, but if he has a full-time job, I don’t think 30-plus homers is out of the question. If he can do that with a batting average around .260 fantasy owners will have gotten their money’s worth. I’m gonna say Reyes’ second half was mostly real, but he carries some risk because of the Padres outfield crunch.

Adalberto Mondesi, SS, Kansas City Royals
2018 Breakout hitter Adalberto Mondesi

I have to be honest, I’d heard this guy’s name for so long and been so unimpressed by his minor league numbers that I completely ignored him when he got called up last year. In fact, I didn’t really realize what he was doing until the last couple weeks of the season. Oops. Mondesi ended up being one of the most valuable players of the second half with his power/speed blend.

I want to say he was a complete fluke. I really do. I was never high on him and I still don’t like a lot of things about him, but the things he can do are going to be very valuable in 2019 fantasy baseball.

Let’s start with the negatives. They aren’t small. Mondesi will not take a walk. His 3.8 BB% should be a crime for players with his speed. He also strikes out too much. He struck out in 26.5 percent of his MLB at-bats in 2018 and 36.7 in 2017. Again, when you have speed like he does, it helps to put the ball in play. So to be clear, on the offensive side at least, Mondesi is a bigger asset in fantasy than he is in real baseball and isn’t the player he could be.

But oh how nice that power/speed package looked for owners who took a shot on him in 2018. Is it real? First off there is no doubting the speed. A FanGraphs Spd score of 7.0 is considered excellent. Mondesi posted an 8.6. The Royals are going to let Mondesi, Whit Merrifield, and Billy Hamilton run until they drop. Unless Mondesi gets hurt, I have little doubt that he can reach 50 steals. The 71 extrapolated above? I’m not sure that .306 OBP gives him enough opportunities.

But what about the bat? I think it’ll be hard for him to hit .276 again, but that .335 BABIP is not too out of line for a player with his speed. His minor league BABIPs are all over the place, so it’s hard to say where it goes from here. Mondesi has generally been pretty balanced when it comes to GB/FB ratio, so the BABIP could be lower, but then maybe that helps when we got to the power we’re all wondering about. And power may be a strong word. Mondesi is more of a pop guy, but his 19.7 HR/FB% isn’t too outlandish. He had seasons of 15.2% and 14.6% at different stops in the minor leagues. I’m not expecting the 31 homers in his extrapolation, but assuming he gets those 600-plus plate appearances, a 13.0 HR/FB% puts him in the low 20’s for home runs.

So is Mondesi gonna live up to that extrapolation? No, of course not. No player in baseball could. He could steal 40-to-50 bases and pop 15-to-25 homers though, and unless you’re in an OBP league his .255ish average won’t hurt too much. Just hope the rest of your league was all wrapped up in football last August and September.

Ryan O’Hearn, 1B, Kansas City Royals
Ryan O'Hearn

Ryan who? Yeah, that’s what I thought. O’Hearn pulled a little Matt Olson circa 2017, but nobody seemed to notice. O’Hearn came with very little prospect hype and a look at his minor league numbers should tell you why. He’s shown some power, hitting over 20 homers in each of the last four seasons rising from Single-A to his debut last year. Of course, that power came attached to batting averages in the .250’s and .260’s. There’s a very real risk of a sub-.250 average in O’Hearn. His strikeouts will ensure that.

But what about that power? As it stands now he has virtually no competition for the first base job in Kansas City, so if he can flash anything close to what he did in 2018, he’s gonna get the PT. Look through his minor league stats and you’ll see HR/FB%’s of 24.5, 26.8, 30.4, and 28.6. Those seem to indicate that 25 percent of his fly balls leaving the yard in 2018 was not a complete fluke. It’s also promising that he seemed to be focused on elevating the ball as his 46.2 percent fly ball rate in Kansas City and 44.6 in Triple-A were the highest of his career. He’s joined the launch angle revolution!

Beware that batting average though. O’Hearn hit just .108 against left-handers in 2018. Sure it was just in 41 plate appearances, but if he’s not platooned I could see an average a lot closer to .225 than .250.

The trouble with lefties and strikeouts mean I’m not completely sold on Ryan O’Hearn in 2019, but if I’m short on power late in drafts, I’ll take a late-round flyer.

Early 2019 Fantasy Baseball Rankings: C | 1B | 2B | 3B | SS | OF | SP | RP | Top 300

Lourdes Gurriel Jr., SS, Toronto Blue Jays
Lourdes Gurriel went completely under the radar

I have to be honest. I saw Gurriel when he came through Dunedin in 2017 and was unimpressed. He was very lean, definitely not looking like he possessed the strength to hit for any type of real power. It was just one game, but I came away with the impression that he would be a light-hitting backup infielder.

Flash forward to late 2018 and I was more impressed. His swing looked a lot quicker and the ball was jumping off his bat. He used that swing to pop 11 home runs in just 249 at-bats and managed a .281 average. Like Mondesi, Gurriel hasn’t seen a pitch he doesn’t like. These two young hitters make Javier Baez look outright finicky. Can they thrive like Baez has with that uber-aggressive approach?

While Mondesi can do it with his legs, Gurriel is gonna have to do it with his bat. The upside is not extreme. In a very deep shortstop pool, Gurriel will not stand out in any one category. There is nothing in his peripherals however, that says his small sample size in 2018 was a fluke. The 17.5 HR/FB% may be a bit elevated, but it’s something that started in Triple-A last season. He’s the shortstop you wait for, not the shortstop you reach for. Expect an average in the .265 range with 20 to 25 homers, and if you play in an OBP league you need to look elsewhere.

Luke Voit, 1B, New York Yankees
Is Luke Voit more than a Quad-A player?

I knew Voit was hot over the second half of the season, but that’s a serious binge right there. We know he’s not that good, but can he be a serious source of power at least, or is he the quad-A bat we thought he was?

Let’s start with the obvious. The 40.5 HR/FB% is unsustainable. His previous high at any level of baseball was 14.4. Let’s say 15 percent of Voit’s fly balls leave the yard. Then let’s pretend he also somehow gets 500-plus at-bats. That puts him right around 20 home runs. Not quite the Ruthian act he put on in the second half of 2018. Need more cold water? His 2018 BABIP of .365 is also way out of his norm. He does have surprisingly high BABIPs on his minor league record, but he’s not a fast runner. Anything over .320 is probably wishful thinking.

We haven’t even talked about playing time yet. How confident are you the Yankees are just going to give the position to Voit? What if Greg Bird has another one of his patented spring training power binges? They’re not real happy with Miguel Andujar’s defense at third base. Could they sign a Mike Moustakas type in January and shift Andujar over to first? I’m not sold on Voit as an everyday player and I bet the Yankees have their concerns. He’s a useful bat with a chance to produce mixed league value in that lineup, but he’s nowhere close to being the type of player he was 2018.

Tyler Austin, OF/1B, New York Yankees
Tyler Austin and cheap power

I have to be honest. I had Tyler Austin in mind for this article before the Twins went and claimed C.J. Cron. It looked like Austin had a free shot at the first base job in Minnesota, now he joins a crowded mix fighting for at-bats between first base and DH. In addition to Cron, Jake Cave and Willians Austudillo will likely get considerable at-bats in the DH slot. Does Austin have what it takes to make them irrelevant? Let’s take a gander.

There’s no doubting Austin’s power. He’s had HR/FB rate has been over 20 percent in seven different stops over the last three years… Yeah, he has moved around a lot. So yeah, he’s got 30-HR type power. The problems start appearing when you look at the strikeout numbers. Austin has a 36.6 percent strikeout rate in his 367 Major League at-bats and the numbers haven’t been much different during his minor league career. So a .270 batting average is just a pipe dream. He earned his 2018 average of .230. On the positive side his splits are pretty neutral so he should be able to hit .230 with power against a variety of pitchers… As Bill Murray would say, “He’s got that going for him.”

Austin could approach 30 home runs if given enough at-bats, but it’s gonna hurt a little bit to get those. He’s not gonna run and that Twins lineup doesn’t look like it will provide a bunch of RBI opportunities. Basically he’s a right-hand Ryan O’Hearn. They might have a role to play on your fantasy team, but it’s not as your next star slugger.

Doug Anderson is a 10-year veteran of the Fantasy Sports industry. His work has appeared on,,, and, as well as in the pages of USA Today’s Fantasy Baseball Weekly and various other magazines. Doug has participated in both LABR and Tout Wars, the two preeminent expert fantasy baseball leagues in existence. Doug was formerly the Executive Editor at RotoExperts and is now Managing Editor here at FantraxHQ. You can follow him on Twitter @RotoDaddy.

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  1. Jorge Calzada says

    I expected to see Ramon Laureano from the A’s in this list. Will he be a regular OF next season?

    1. Doug Andersen says

      Yeah, I certainly could have included Laureano in here. His numbers kind of sneak up on you. Barring new acquisitions he should have the CF job to himself. I wouldn’t be surprised to see an average in the .260’s, but with the PT he’ll have some sneaky power/speed value. Here’s his extrapolation from his 2018 at-bats.
      Ramon Laureano

  2. Chris in The ICT says

    Was hoping to see Tyler White here. Has he done enough to earn the full-time DH spot?

    1. Doug Andersen says

      Yeah, he’s a player I probably should have had in here. Unless he has a terrible spring training and Kyle Tucker lights it up, White should get his shot at the DH job to start the year. Really nothing in his peripherals that says 2018 was a fluke. Probably should have been a full-time player by now. Just had the bad fortune to go into a funk in 2016 in his only other real shot at full-time at-bats. I like him as a .275, 25-HR type. Not flashy, but in that lineup that could equal plenty of counting stats.
      Tyler White Extrapolation

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