Know Your Orioles 40-man: Ryan Mountcastle

This article is part of the Know Your Orioles 40-man series, which features an article about each player currently on the Orioles roster. There will be one every weekday until we run out of players.

There was a time, back in 2019, when you worried for Ryan Mountcastle. The hard-hitting youngster, who won International League MVP honors that season, was mashing Triple-A pitching with a .312 average, 25 homers and .871 OPS campaign. Fans were begging Mike Elias to let Mountcastle up to the bigs. Yet amidst a sea of evasive pronouncements by the O’s GM, Mountcastle’s MLB arrival seemed indefinitely delayed.

Part of it was no fault of his own: first base, a natural fit for the 6’4” power-hitting righty, was blocked by the most expensive Oriole of all time, Chris Davis, who between 2015 (the year Mountcastle was drafted) and 2020 never made fewer than 97 starts at first base in any season, even as guys like Trey Mancini and Renato Núñez started eclipsing his offensive output.

Part of it was due to Mountcastle’s own evident limitations as a prospect. As Fangraphs put it in 2020: “Beware the swing-happy hitter with no position.” A shortstop by trade, when Mountcastle’s size and weak arm edged him out of the position, the Orioles started working him out at third base, then left field, hoping to give him some path to the majors that wouldn’t involve the logjam at first.

The other perceived problem with Mountcastle, as Fangraphs pointed out, was his batting eye. If you’re into nitpicking, one blemish on his 2019 MVP season with Norfolk was a measly walk rate of 4.3%. In five minor-league seasons, Mountcastle never walked more than 26 times. His minors career .295 batting average stands out, but so does (and not in a good way) an OBP just 33 percentage points higher. Back in 2019, even the hard-to-pin-down Mike Elias was clear as to the righty’s assignment: work on the outfield defense and the plate discipline, and maybe then a call-up would follow.

On August 21, 2020, the Orioles gave the 23-year-old his chance. He came as advertised, mashing in 35 games that season to finish with a .333 batting average, 23 RBIs and a 137 OPS+. In 2021, with the exception of a horrific April/May, he mashed some more, hitting 33 home runs to lead all rookies and eclipse Cal Ripken Jr.’s franchise rookie home run record of 28.

Did Mountcastle’s promotion mean he’d fixed his outfield game the way the Orioles hoped? You be the judge: according to Fangraphs, in just 46 games as an outfielder Mountcastle has cost the Orioles an impressive 20 runs. It is probably time to call that experiment a failure. Fortunately, though, he won’t be using his outfielder’s glove much next season. Chris Davis’ April 2021 retirement allowed the O’s to split 1B/DH duties between Mountcastle and Trey Mancini, making his heroic return after a malignant cancer diagnosis in 2020. Neither exactly threatened for a Gold Glove in 2021, but Fangraphs actually ranks Mountcastle as a plus defender at first, with three runs saved per UZR. While Baseball Savant is cooler on Mountcastle’s glove (valuing him at -4 outs above average), if his offense is at all as advertised, just so-so defense will keep him in the lineup every time.

As for that offense, you’ll recall that Mountcastle’s other homework assignment was to take more walks. Here, the results are positive, in fact: a perfectly average 7.9% walk rate in 2020 and a slightly below-average 7.0% mark in 2021. That’s not Joey Gallo territory, but for a guy who averaged a 4.6% career walk rate in the minors, it looks like Ryan Mountcastle is evolving as a hitter.

There’s further proof of Mountcastle’s continuing plate adjustments: what he did with offspeed pitches in 2021. After the rookie tagged fastballs to the tune of .356 in 2020, pitchers started to feed him more breaking stuff in 2021. Over the month of April, Mountcastle saw fewer heaters and more curveballs and sliders than he ever had—and the results were pretty grim. His average against breaking balls sank to .167, and he whiffed at career-high levels, a ghastly 40.9% K rate. During that stretch, in 188 plate appearances, he walked just seven times, a lowly 3.7% rate.

But after those spring struggles, Mountcastle started to look like himself again. In June, he slashed .327/.382/.634 with a 1.015 OPS, nine home runs, 26 RBI and 64 total bases to win AL Rookie of the Month honors. In August, some of his stats were even gaudier: a .786 slugging percentage and a 1.183 OPS, third in the Majors behind only C.J. Cron and Bryce Harper. Tellingly, Mountcastle averaged .362 on breaking balls those two months, and eventually, pitchers stopped throwing him so many.

Getting to the MLB in 2020 and acing a 35-game audition is one thing. But hitting rock-bottom in April and May and recovering to produce arguably the best power-hitting season by a rookie in Orioles franchise history is another. Besides the 33 home runs, Mountcastle finished second among rookies with 89 RBI and from May-October led all rookies with a .528 slugging percentage and .853 OPS. He didn’t get close to ROY honors (blame his average defense and the stunning debut of Randy Arozarena) but at the plate, Mountcastle made more noise than any of them. Manager Brandon Hyde admitted that while the rookie’s first half was not “all sunshine and rainbows,” over the season he matured “an incredible amount.”

I’m sure Ryan Mountcastle is very aware of the items still on his to-do list: walk more, whiff less. His chase rate is still in the top 3% of all hitters, and his walk rate in the bottom 14%. But there are few hitters who can hit the ball harder than Mountcastle does. Choose your spots and hit them hard: easy to say, hard to execute. Mountcastle has room to go on the former, but the good batted-ball data speaks for itself.

Until last season, when it came to Ryan Mountcastle the oft-stated concern of the front office was making sure that he was promoted to the big leagues only when they felt he was ready to stick there. Heading in 2022, that’s no longer the worry.

End-of-season prediction: In 2021, the Orioles allowed Mountcastle and Trey Mancini to get a full season’s worth of at-bats while splitting 1B/DH duties. For now, I’m going to cover my eyes and pretend I haven’t seen the unpleasant rumors that the O’s could take advantage of 15 new DH spots opening up in the NL to move Mancini. From the point of view of Ryan Mountcastle’s continued development as a hitter, though, it probably doesn’t much matter either way. I predict that Ryan Mountcastle finishes 2022 in the majors as the Orioles’ everyday first baseman.

Previously: Félix Bautista, Logan Gillaspie, Isaac Mattson, Cionel Pérez, Bryan Baker, Rougned Odor, Joey Krehbiel, Tyler Nevin, Kyle Bradish, Rylan Bannon, Yusniel Díaz, Kelvin Gutiérrez, Kevin Smith, Terrin Vavra, D.L. Hall, Jahmai Jones, Bruce Zimmermann, Mike Baumann, Ryan McKenna, Dean Kremer, Keegan Akin, Jorge López, Ramón Urías, Dillon Tate, Paul Fry, Zac Lowther, Alexander Wells, Cole Sulser, Jorge Mateo, Tanner Scott, DJ Stewart

Tomorrow: Tyler Wells