Under the Radar: Is Jacob Lopez’s Breakout For Real?

The Athletics raced out to an impressive start this season. They finished April with a 16-15 record and sat 2.5 games back of the Seattle Mariners in the American League West. Now-starting pitcher Jacob Lopez made his season debut on April 18th as a reliever, and while the Athletics have struggled since then – their 54 losses rank fourth in MLB – his standing among fantasy baseball pitchers has done nothing but shoot upward. Lopez is putting together an excellent season, but should we buy into his breakout campaign?

Is Jacob Lopez for Real?

Green Flags

His 2025 Performance Puts Him in Elite Company

There are 198 starters (min. 50% GS) with at least 20 IP this season.

Of those pitchers, 18 boast a strikeout rate of at least 1.2 batters per inning. That group includes elite arms like Tarik Skubal, Garrett Crochet, Chris Sale, Zack Wheeler, Jacob Misiorowski, and MacKenzie Gore. The average ERA of said pitchers is roughly 3.50, and 44% have an ERA under 3.00.

Among pitchers with at least 1.25 plate appearances per team game (Baseball Savant’s percentile qualifier), 12 rank in the 70th percentile or above in all the following categories: xBA, Barrel Rate, Average EV, Hard-Hit Rate, Strikeout Rate, and Whiff Rate. Among that group? Zack Wheeler, Hunter Brown, Tarik Skubal, and Garrett Crochet.

Lopez has a seat at both tables, which speaks to how well he’s performed so far this season. Despite pitching in a very hitter-friendly ballpark, he has pitched to a 3.99 ERA and notched 84 strikeouts in 70 innings pitched.

He Has Excellent Expected Statistics

With an xERA of 3.68, the Athletics left-hander has the quality-of-contact metrics to back up his performance. Additionally, his .217 xBA indicates perhaps his .237 opponent AVG and 1.34 WHIP should be a tad lower.

During the month of July, Lopez posted a .206 xBA. That’s the lowest mark he’s had all season, which indicates his success in the early going may not be a fluke. His two most-used offerings – a four-seam fastball and slider – carry expected batting averages of .177 and .198, respectively.

Red Flags

High Pull AIR%

Pitching at Sutter Health Park is not ideal for a fly-ball pitcher. Just over 18% of fly balls – roughly one in every five fly balls – are home runs at the Athletics’ venue. That’s the fourth-highest fly ball to home run ratio among MLB stadiums, trailing only Dodger Stadium, Camden Yards, and Angel Stadium. And according to Baseball Savant’s Park Factors, it’s the seventh-most home-run-friendly ballpark in baseball.

Lopez has a 2nd-percentile ground ball rate (25.8%), which doesn’t bode well for the rest of the season. And batters aren’t just lifting the ball against him – they’re pulling the ball at a very high rate, which is a recipe for home runs. Among the 335 MLB pitchers who have allowed 100+ balls in play, Lopez ranks 10th in Pull AIR%. That’s a sign that his 79th-percentile Barrel% could be misleading.

Subpar Stuff, Declining Command

Not one of Lopez’s five offerings grades out as above-average by Stuff+. His slider comes close – it’s a 99, where 100 is average. And by Run Value, it has been his most valuable pitch by far; no other offering has eclipsed zero runs, while his slider currently sits at four runs.

But when it comes to his other offerings – a four-seam fastball, cutter, changeup, and sinker – Lopez’s stuff is not up to standard. Those four offerings have Stuff+ ratings of 91, 89, 83, and 82, respectively. The left-hander’s fastball averages 90.7 MPH, which is reason to be skeptical he’ll continue to post 81st-percentile strikeout rates.

While he did strike out batters at a high rate in the minor leagues – including 231 punchouts in 195 innings pitched during his time in Triple-A – his stuff indicates that his strikeout rates will likely fall as the season progresses.

To make up for his less-than-electric stuff, Lopez has relied on exceptional command. His slider boasts a Location+, which means he locates it extremely well. Add on a sinker he throws with well-above-average command and the occasional well-placed cutter, and the former 26th-round draft pick has a variety of weapons he can throw to any part of the zone.

In July, however, Lopez’s walk rate spiked to 12.3%. That coincided with a drop in whiff rate and a significant uptick in opponent slugging percentage (.368 to .443), which is concerning.

Lopez’s walk and strikeout rates contribute to his 4.36 xFIP, which is nearly 70 points higher than his 3.68 xERA. When combined with his high home run risk, Lopez’s ERA floor is lowered significantly from what we might initially assume.

So, which version of Jacob Lopez is for real? For rotisserie-league managers who are willing to accept home run risk for strikeout upside, he’s a viable starting pitcher option. Fantasy managers do need to keep an eye on his whiff rates, but he is a great streaming option against teams with low fly-ball and contact rates. Only time will tell which version of Lopez the Athletics – and fantasy managers – get in the final two months of the season.

Remember to check back next week for more Under the Radar players and analysis.