Two MLB April callups thriving in the majors, two that are struggling

The month of April brought baseball fans a few highly anticipated prospects with sky-high potential. While some of these recent call-ups are off to a strong start, others haven’t quite lived up to their potential as of yet. Now in their second month of action, let’s review four such callups: two off to promising starts and two off to underwhelming starts. 

Promising starts 

Chase Meidroth, IF, White Sox

Meidroth, Chicago's No. 8 prospect, was coming off a 2024 campaign where he hit .293/.437/.400 with seven home runs across 437 at-bats in the Red Sox farm system before being traded for Garrett Crochet. A proven hit over power prospect, Meidroth posted an uncharacteristic three home runs in thirty at-bats with the Charlotte Knights before making his MLB debut.

Now in the majors, Meidroth is hitting .284/.370/.358 with one home run and five stolen bases in as many attempts. As expected, Meidroth’s contact-hitting skills are far outpacing his fringy power, but the stat that truly stands out is his .370 on-base percentage. This is thanks to his low strikeout-to-walk ratio, having taken 11 free bases compared to 14 strikeouts. His untarnished stolen base record is also impressive for a player lacking plus speed.

Agustin Ramirez, C, Marlins

Ramirez, the club's No. 4 prospect (No. 97 overall on MLB Pipeline), didn't waste much time when it comes to showcasing his power. Across three minor-league levels last season, Ramirez hit .267/.358/.487 with 25 home runs and a surprising 22 stolen bases, not a trait common for a catcher.

In 82 at-bats with the Marlins this season, Ramirez is hitting .268/.341/573 with five home runs. His five longballs tie him for second in the stat among rookies behind only Dylan Crews, who has almost twice as many at-bats. He is also tied for first in doubles among rookies with 10 and, like with Crews, has seen only about half the at-bats as the other two hitters he’s tied with.

Underwhelming starts 

Chase Dollander, P, Rockies

One of the game’s elite prospects, ranking No. 22 overall, Dollander is without a doubt a rookie to watch. The Rockies’ top prospect boasts an electric arsenal, finishing his 2024 campaign with a 2.25 ERA and 169 strikeouts in just 118 innings across two minor-league levels. Dollander was promoted to Triple-A to start the season and only pitched four innings before being called up.

Having started eight MLB games, Dollander’s ERA sits at 6.28. In 38.2 innings, he has given up 10 home runs (worst among all rookie pitchers) to an opponent batting average of .248. This might be partially blamed on the "Coors Field effect," characterized by the Mile High City’s hitter-friendly atmosphere. Dollander maintains a frightening 8.66 ERA at his home park this season. But regardless of the venue, the young righty still hasn’t quite figured out major-league hitters, as evidenced by his 4.29 ERA on the road.

Caleb Durbin, IF, Brewers

Durbin, Milwaukee's No. 21 prospect, is a rather exciting trade piece received from the Yankees for Devin Williams. Durbin possesses staggering speed, a keen sense of the strike zone and great bat-to-ball skills. Last season with the Triple-A RailRiders, Durbin hit .275/.388/.451 with 10 home runs and 40 steals in 335 at-bats. Throughout his minor-league career, he walked a total of 137 times compared to 116 strikeouts. His 29 stolen bases in the 2024 Arizona Fall League is a league record.

Since getting the call, Durbin has struggled to hit, slashing just .169/.263/.241 with one home run in 83 at-bats. His batting average lags every rookie with at least 70 at-bats and his speed doesn’t appear to have the same effect it did in the minors, as he's stolen just one base in two attempts.