Fantasy Baseball Overvalued and Undervalued – Week 5

It’s tough to call any fantasy baseball players overvalued or undervalued a little more than one month into a new season. No team has played more than 40 games, and sample sizes are tiny compared to what we normally need to make long-term judgments on players.

However, based on early performance, team usage, and changes to a player’s approach or mechanics, it’s already clear some players were undervalued in fantasy baseball draft rooms while others appear to have been overvalued.

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This weekly piece will look at the past seven days of fantasy baseball performances to see who should be considered overvalued and undervalued going forward. When necessary, I will reference the Fantrax top 400 rotisserie rankings for the 2026 fantasy baseball season.

Fantasy Baseball’s Most Undervalued Players

(Stats are up to date as of April 28)

JJ Wetherholt (2B/SS/3B – STL)

JJ Wetherholt was a top prospect heading into 2026, so it’s not like this is a name out of nowhere, but his immediate rise to stardom may have slipped past a lot of radars so far. The Cardinals put him in a perfect role right away, especially for their team context in 2026. St. Louis immediately trusted him as an everyday player and gave him leadoff opportunities, which has maximized his run-scoring and stolen-base value. Overall, he is hitting .238/.359/.429 with six home runs and four steals.

Overall, he makes a ton of contact, avoids chasing pitches, and already looks comfortable hitting near the top of the lineup. His hard-hit numbers in Triple-A were excellent, including a 91.4 mph average exit velocity and a 48.1% hard-hit rate, showing that the power is real and not just a product of minor league pitching. That has translated to MLB (45.2% hard-hit rate), and Wetherholt may just be starting to scratch the surface of what he can do.

Christian Walker (1B – HOU)

If you’re like me, you wrote off Christian Walker completely after his disastrous 2025 season. His first year with the Houston Astros ended with some decent power numbers (27 home runs and 88 RBI), but he really didn’t get going until after the All-Star Break, and finished with a .238/.297/.421 line and a 28% strikeout rate.

In 2026, he has turned that around and started out very hot. He is hitting .291/.373/.573 with seven home runs and 23 RBI. Most importantly, he has lowered his strikeout rate to 18% and boosted his walk rate to 11%. His BABIP is a reasonable .307, so there is not a lot of luck here. This is just Walker using his power and a strong 43% flyball rate to get back to where he was when he was mashing with Arizona.

Landon Roupp (SP – SFG)

In the first five weeks of the fantasy baseball season, three pitchers have five wins. One of them (Chris Sale) is an ace. Another (Jose Soriano) is the year’s biggest breakout story. The third is Landon Roupp, after he rolled past the Marlins for his fourth straight win a couple of days ago.

In his first season as an MLB starter, Landon Roupp was a perfectly servicable pitcher for fantasy leagues in 2025. Across 22 starts, Roupp had a 3.80 ERA and struck out almost a batter per inning. But if his 2026 ends up looking anything like his last four starts, Roupp could be one of the breakout pitchers of the year.

Roupp pitched 7.2 innings, had a 0.52 WHIP, and struck out six. The reason for the success might have to do with his pitch mix. He essentially does not throw any four-seam fastballs (1.9%). Instead, he focuses on his sinker (39%) and his curveball (29%). This has had outstanding results, and we can expect Roupp to deploy a similar arsenal through the rest of the season.

Fantasy Baseball’s Most Overvalued Players

Fernando Tatis Jr. (OF – SDP)

Fernando Tatis Jr. is 27 years old this year. This is supposed to be his prime, peak-age season. So what has happened so far? Tatis has given fantasy managers a disappointing .257/.336/.295 line with absolutely zero home runs. That slugging rate (below .300) is like a punch in the face for a player who has been so elite for so long.

Tatis’s 94.6 miles per hour (MPH) average exit velocity and 67% hard-hit rate are elite, and he is still showing more than a 10% walk rate. That clearly shows more discipline at the plate, but it just hasn’t resulted in much power, and more than a month into the season, it’s becoming a huge problem for fantasy managers.

If Tatis is going to turn things around, he is going to have to do something about a career-high 50% groundball rate and a career-low 26.9% flyball rate. Can a correction here lead to some home runs? Sure, it can, but Tatis needs to start showing he can actually do it.

Roman Anthony (OF – BOS)

Is Roman Anthony really this bad, or is he just caught up in the general destruction that has defined the Boston Red Sox to begin the season? He is hitting .218/.358/.310 with one homer and two steals coming into Tuesday night, and then had another 0-for-4 night with a strikeout. His hard-hit rate, barrel rate, and exit velocity are all down from last year, which is odd considering how well he fared in the minors.

Anthony destroyed the two levels of the Minor Leagues he played in during 2024 and a short time in 2025. Combined, he hit .291/.396/.498 with 18 home runs and 21 stolen bases. That .396 OBP is no fluke, as his numbers in 2022 and 2023 were in that range as well. But perhaps the most striking thing about Anthony is that he was already this polished at the plate and with the glove at just 21 years old.

Somewhere in there is a superstar ready to break out, but for a player who was drafted inside the top 40 hitters, this is about as disappointing as it gets.

Cole Ragans (SP – KCR)

In fantasy baseball, our stars at least need to be consistent, especially if they are not going to be elite every time they take the mound or every time they step up to the plate. This year, Cole Ragans has been the exact opposite of consistent. In fact, his pattern of starts is fascinating. In his second, fourth, and sixth starts this season, he has a combined ERA of 0.50. In his first, third, and fifth starts, he has not come away with an ERA below 9.00 in any of them.

He has games with 11 strikeouts and games with one. He dominated the Tigers, but got smoked by the Guardians (and didn’t make it out of the first inning). Ragans showed in his last start (one run, 11 Ks) that he still has ace stuff. But right now, he is ranked outside the top 300 pitchers on all player raters because his ERA is above 5.00 and his WHIP is 1.48. Until he can consistently go deep in games and keep men off base, this is a place to exercise caution.