Mountcastle’s struggles and O’Hearn’s breakout create uncertainty about Orioles’ future at first

Coming into the 2023 season, first base was hardly a position that most members of Birdland worried about. While Ryan Mountcastle didn’t engender the same level of confidence as an Adley Rutschman or a Cedric Mullins, he’d still been an incredibly productive member of the Orioles lineup since becoming a starter in 2021. Over his first two full seasons in the big leagues, Mountcastle put up 51 2Bs, 55 HRs and 174 RBIs—while also providing capable defense at first. Anthony Castrovince of MLB.com even went as far as naming RMC as a member of his All-Underrated team for the 2023 season.

However, the start of the 26-year old’s third full season has hardly gone to plan. His batting average and on-base percentage has continued a worrying downward trend. Mountcastle’s .227 average is 19 points below league average, while his on-base percentage at .264 is 56 points below the MLB mean. The 2023 hasn’t helped Mountcastle’s reputation as an incredibly unlucky player, as his xwOBA and xBA both rank well above average, but he’s developed the unfortunate habit of hitting it hard right at defenders.

What can’t be explained away with poor luck though is RMC’s lack of discipline. So far this year, the O’s first baseman ranks in the third-percentile in chase rate, the sixth-percentile in walk rate and well below average in K and whiff rates. Sure, when Mountcastle makes contact he tends to hit the ball hard, but too often he’s swinging at bad pitches and failing to make contact at all. To make matter worse, Mountcastle recently went on the IL with a bout of vertigo and it’s unclear when he might return to action.

However, the good news for the O’s and Birdland is that Ryan O’Hearn has stepped in for Mountcastle and outperformed even the most optimistic expectations. A former 8th-round pick out Sam Houston State (the same program that produced Colton Cowser), O’Hearn came to the O’s as somewhat of an offseason afterthought. He joined the likes of Josh Lester and Lewin Diaz as token attempts by the front office to added left-handed power bats to the organizational depth chart.

Over parts of five seasons with the Royals, O’Hearn showed moments of promising power that were rightfully overshadowed by a lack of consistency in his production. After slashing .262/.353/.597 with 12 HRs and 30 RBIs in 149 ABs as a rookie, ROH never managed to recapture that form. Next year in 2019, O’Hearn but up 14 HRs and 38 RBIs in 328 ABs, but his triple took a massive drop down to .195/.281/.369.

The big lefty from Texas often struggled to lift the ball throughout his time in Kansas City, as his ground ball rate jumped from 35% as a rookie into the mid to upper 40s the rest of his time as a Royal. O’Hearn also continually struggled with breaking balls throughout his time in the AL Central. After hitting .250 against breaking balls as a rookie, O’Hearn never managed to above .174 against sliders and curves in the ensuing four seasons. To compare O’Hearn’s time as a Royal to Chris Davis’ time in Texas would on one hand be apt, but on the other hand a bit unkind to Davis.

That’s what makes O’Hearn’s rise to prominence in Baltimore’s lineup all that more surprising. A player who hit .211 over the last four seasons is now one of the hottest hitters in the American League. Since the beginning of June, O’Hearn’s .425 average and 1.117 but him in the company of players like Corey Seager and Shohei Ohtani—players who will surely represent the AL in Seattle next month.

Many of the issues O’Hearn had in KC have only been slightly remedied in his time as an Oriole. He’s still hitting more ground balls than fly balls—his fly ball rate is the highest it’s been since his rookie year. His barrel rate, average exit velocity and average launch angle have all seen slight bumps, but nothing that would suggest the breakout that sees him hitting .349 with an OPS over 1.000.

The biggest difference for O’Hearn this season is how he’s approaching breaking balls. After swinging after over 45% of breaking balls over the last two season, that rate has dropped 31.6% in 2023. O’Hearn has also drastically cut his chase rate on big breaker, from 37.6% in 2022 down to 17.5% this season. This more selective approach against breaking balls has seen the lefty become more aggressive against fastballs and offspeed offerings, and this retooled approach sees O’Hearn hitting .333 or better against all pitch groups this season. O’Hearn is making more consistent contact than ever before and consistently driving the ball over the park.

For all those already heading to the comments to say we should pump the breaks on the O’Hearn love: yes, this success has come in the small sample size of 83 ABs. And yes, the .414 BABIP O’Hearn currently sports is absolutely unsustainable. However, neither of those caveats should take away from the phenomenal production that’s earned O’Hearn his place in the lineup.

As long as O’Hearn continues to hit anywhere this well, it presents a potential headache for Brandon Hyde once Mountcastle is healthy. An easy answer is to do a straight platoon—O’Hearn starting against right-handers and Mountcastle starting against lefties. After all, despite his overall struggles is hitting .311 against southpaws. However, if that’s the approach the O’s take, it sparks questions as to how much of a permanent fixture Mountcastle will be going forward.

The development of players in Baltimore and the minors means that the competition for roster spots for position players will only become fiercer this season and next. If Mountcastle is reduced to a platoon player that only hits lefties, it’s worth considering whether he can stick on the roster long term. O’Hearn’s presence only make the future for RMC even more dubious, and it’s a storyline we’ll all have to keep track of in the second half of this season.