What should we expect out of Orioles rookie Ryan Mountcastle?

His time has finally arrived. After five minor league seasons and a few extra weeks spent at the pandemic-necessitated alternate site in Bowie, Ryan Mountcastle is a big leaguer. The Orioles promoted the young slugger on Friday, and they have since made him their everyday left fielder.

Mountcastle’s promotion was highly anticipated by the Orioles fanbase, and the club’s unexpected early-season success exacerbated those feelings.

Who can blame us? Mountcastle is a former first-round pick. He has been a consensus Top 100 prospect for a couple of years now. He has been an above-average hitter at every minor league level. And he is viewed as a fairly important piece of the next competitive Orioles team. Fans want to see what he can do and deserve to be excited.

To his credit, the early returns have been pretty good. Across three games, Mountcastle has gone 3-for-9 with two doubles, two runs, three walks and three strikeouts. It’s a promising start to what will hopefully be a long and successful career.

What can get lost in the excitement of a highly-touted prospect’s big league debut is the realistic potential of said prospect. So, let’s take a step back, examine Mountcastle, and remember what type of production we can expect from the 23-year-old.

This blog might be more enjoyable if we get the negative stuff out of the way first, so let’s talk defense.

If you have been following Mountcastle’s minor league climb even a little bit, then you know that the whole fielding and throwing part of the game is where he is less refined.

MLB Pipeline’s scouting report on the Florida native explains that he possesses “a below-average arm and limited range.” FanGraphs adds to that by saying “beware the swing-happy hitter with no position” and clarifies that Mountcastle has “had issues throwing to first base.”

There is no need to read between the lines there. It is written plain as day. Mountcastle is a bad fielder. In all likelihood, he will provide negative value on defense regardless of where he plays. In a perfect world, he would DH. But the Orioles are going to give him a glove for the time being and see how it goes. At the very least, they will hope he is an improvement over Dwight Smith Jr., who had proven to be a butcher in the field during his time in the organization.

As poor as Mountcastle may end up being in the field, the Orioles clearly feel that his bat is valuable enough to make it worthwhile. So, let’s take a look at the youngster’s offensive profile.

Mountcastle took home the International League MVP award in 2019 as a member of the Triple-A Norfolk Tides. That’s neat, and he joins the company of some notable major leaguers who won the same award: Rhys Hoskins (2017), Shane Victorino (2005) and Jim Thome (1993). But more often the IL MVP goes to someone who turns into a fairly pedestrian player at the game’s highest level, so don’t clutch onto that honor too firmly.

What matters more is Mountcastle’s production relative to the competition.

Across 127 Triple-A games in 2019, the 2015 draft pick slashed .312/.344/.527 with 25 home runs and a wRC+ of 117. Those are good numbers. Some folks will cite that the Triple-A level was using the juiced MLB balls last year, and consider that to invalidate Mountcastle’s production.

It’s a fair criticism, but it’s not as if Mountcastle’s numbers were completely out of whack with his career arc previous to that season. He owns a .295/.328/.471 slash line over five minor league seasons across six different levels. The guy can hit regardless of the ball being used.

What has caused more concern is Mountcastle’s plate discipline. He walked 4.3% of the time in 2019 while striking out 23.5% of the time. Those numbers represented more of the same as his earlier work on the farm. In fact, they were actually a step down from a 6.1% walk rate and 18.5% strikeout rate with Double-A Bowie in 2018.

If Mountcastle were to carry those rates directly into the big leagues they would not be ideal. However, they are bearable as long as he provides some power behind them.

It’s also worth mentioning that, at just 23 years old, Mountcastle is significantly younger than most big leaguers. As he gets more comfortable, he should continue to improve. That’s not to say he will develop a Joey Votto-esque approach at the plate. But it’s not unreasonable to believe he could walk more in the majors that he did in Triple-A.

That brings us to an always fun, rarely accurate point of an evaluation: player comparisons. Which established big leaguer will Mountcastle echo in his career?

If you want to look to a recent Oriole, Jonathan Schoop feels like a reasonable comp on the offensive side of things. In 70 games with the 2013 Norfolk Tides, Schoop posted a 4.5% walk rate and 19.0% strikeout rate. He has since walked in just 3.8% of plate appearances and struck out in 23% of plate appearances as a big leaguer. Meanwhile, he also provided some thunder, including a 2017 season in which he smacked 32 home runs and made an All-Star team.

A non-Orioles player who fits Mountcastle’s overall profile a bit more is Reds outfielder Nick Castellanos. Like Mountcastle, Castellanos was drafted as a third baseman and, after debuting in the bigs as a third baseman, has since fallen down the defensive spectrum due to some issues in the field. Whatever the case, the former first-round pick of the Tigers signed a four-year, $64 million contract with the Reds this past off-season.

Castellanos owns a career 6.5% walk rate and 23.2% strikeout rate while peaking as a 3.0 fWAR player with the 2018 Tigers. He has not yet made an all-star team or won any major awards, but he did generate some Rookie of the Year praise in 2014 and has carved out a nice, productive career.

In all likelihood, Mountcastle will hit enough to be an everyday Oriole for years to come. Whether his at-bats will come as a left fielder, first baseman or DH remains to be seen.

What shouldn’t be expected of him is to be the star of this team for the next decade. Leave that distinction for Adley Rutschman. He won’t lead the league in home runs either, and might not even pace the future Orioles. This year’s first round pick, Heston Kjerstad, is more likely to do that.

Mountcastle has the goods to be a steady, sometimes powerful, force in the middle of the Orioles lineup for the forseeable future. And if some of his prospect peers navigate their way to Baltimore as well, they should all have a hand in sending these O’s back to the playoffs in a few years.