The Orioles announced four roster moves Saturday, including the news that first baseman Ryan Mountcastle has been placed on the 10-day injured list due to a right hamstring strain. Top infield prospect Coby Mayo has been called up from Triple-A Norfolk, and outfielder Jordyn Adams is also heading up from Triple-A after his contract was selected to Baltimore’s active roster. To create space on the 40-man roster, catcher Chadwick Tromp was designated for assignment.
Mountcastle stole home for what ended up as the winning run in the Orioles’ 2-1 win over the White Sox yesterday, but the first baseman left the game a couple of innings later due to what was described just as discomfort in his hamstring. The severity of the strain isn’t yet known, as interim manager Tony Mansolino told reporters (including Matt Weyrich of the Baltimore Sun) that Mountcastle would be undergoing an MRI today.
Like much of the Orioles roster, Mountcastle has gotten off to a rough start in 2025, with just a .246/.280/.348 slash line to show for 200 plate appearances. It is a huge dropoff from the generally solid (112 wRC+) production Mountcastle posted over his first five seasons as a regular in the O’s lineup. Mountcastle has traditionally hit with enough power to overcome subpar walk and strikeout totals, but while his barrel and barrel rates are at his career norms, his Isolated Power is only .102 (far below his .185 career number prior to 2025).
This IL stint could be viewed as a potential reset for Mountcastle’s season in this context, and his absence gives Mayo another shot at establishing himself at the MLB level. Mayo has been called up for a few limited stints in the majors over the last two seasons, and has hit only .094/.186/.094 over 59 PA against big league pitching. Even these extreme struggles can be written off as a small sample size, though Mayo’s domination of Triple-A pitching has also fallen off this year, as he has a modest .226/.318/.452 slash over 195 PA in Norfolk.
It is obviously far too soon to write off a player who has gone from being a fourth-round pick in the 2020 draft to a fixture on top-100 prospect lists. Mayo hasn’t gotten much playing time with Baltimore due to the team’s crowded infield, yet perhaps in monkey’s paw fashion, some opportunity has now arisen due to the Orioles’ disastrous start and the swath of injuries that have taken out most of the everyday lineup.
Mountcastle joins Jordan Westburg, Colton Cowser, Cedric Mullins, Tyler O’Neill, Gary Sanchez, and Ramon Laureano on the long list of Orioles position players on the IL. Between this group and several pitchers also sidelined, the Orioles haven’t been able to make up the depth in stumbling to a 20-36 record.
Westburg and Cowser are both on Triple-A rehab assignments and could be back in relatively short order. With Mullins hitting the IL yesterday, however, the Orioles will shore up their outfield by adding Adams, who inked a minor league contract with the team over the offseason.
Adams has hit only .212/.316/.345 in 136 PA at Triple-A this season, and his big league track record consists of a .176/.205/.216 slash line in 78 PA with the Angels over the 2023-24 seasons. A former first-rounder who received some top-100 attention during his time in the Halos’ farm system, Adams can play all three outfield positions, and is a decent bench option to have on hand until Cowser returns.
Tromp was also a minor league signing in April, and he was selected to the MLB roster earlier this week due to concerns that Adley Rutschman might have required a stint on the seven-day concussion-related IL. Since Rutschman ended up needing just a couple of days off and Maverick Handley is on hand as the backup catcher, Tromp will now head to DFA limbo after making two in-game appearances during his brief time on Baltimore’s roster.
Tromp has seen at least a little action in each of the last six MLB seasons, appearing in 63 total games with the Giants, Braves, and Orioles from 2020-25. Tromp is out of minor league options, and thus the O’s had to designate him and expose him to the waiver wire before trying to send him down to Triple-A. If Tromp clears waivers, he can reject an outright assignment to Triple-A because he has previously been outrighted in his career. It remains to be seen if Tromp may choose to move on from the Orioles given the crowded depth chart of Rutschman, Handley, and Sanchez, as Tromp may prefer to join a team that has more of a clear path to big league playing time.