Ryan Mountcastle Is Having a Weird One

A big part of this gig early in the season has to do with identifying outliers and regression candidates, either to celebrate the former or warn about the latter. The Statcast-based expected statistics have made this job many orders of magnitude easier than it was a decade ago, so I’ve spent much of the past month looking at the league leaders for xwOBA and the like.

Ryan Mountcastle has been up there. Through Monday’s games, he’s 42nd among qualified hitters in xwOBA, one spot ahead of his teammate Adley Rutschman and two ahead of Alex Bregman. More to the point, his actual wOBA (.298) is 92 points lower than his xwOBA, which is the sixth-biggest discrepancy in the majors among qualified hitters.

Mountcastle has been at least a league-average hitter, by wRC+, in every season of his major league career. Is he just getting unlucky in a small sample? I mean, probably, but that’s not the only reason he’s having a weird year.

If you’ve listened to as much Hardcore History as I have, you can only hear the phrase “the extremes of the human experience” in the particular lusty growl Dan Carlin breaks out when he’s about to read a detailed description of some medieval unfortunate being disembowled in a public setting. Which is sort of happening to Mountcastle.

Sure, he’s hitting the ball hard but underperforming his expected stats, but who cares? So is Rob Refsnyder. So is Shohei Ohtani, if you have a strict enough definition of “underperforming.”

Mountcastle is a pretty aggressive hitter. In his first three seasons, he posted walk rates in the 7% range, which is below league average (9.0% this season) but not especially unusual. His chase rate, however, has been in the worst 10% of the league every year of his career, and it’s currently in the second percentile.

Or, if you prefer, Mountcastle hasn’t walked since April 7. He has a nine-RBI game since he walked last. And that walk on April 7 is Mountcastle’s only walk since Opening Day. Feels like anyone who walks just once in 22 games should consult a physician.

Perhaps you can already see what this means for Mountcastle’s stat line. While most hitters get on base without putting the ball in play a few times a week, Mountcastle is generating almost all of his offensive value on balls in play. So it stands to reason that his xwOBA isn’t accurately capturing the extent to which he’s having hard luck once the ball leaves his bat.

Sure enough, if you take only Mountcastle’s numbers on contact, the situation is even more extreme. He has the second-biggest negative discrepancy in the league between his wOBACON and his xwOBACON, behind Josh Naylor. The negative discrepancy between his batting average on contact and his xBACON is the third-largest in baseball, behind Naylor and Alek Thomas. (And nobody’s happy with being denied expected BACON.)

The reason Mountcastle’s expected stats look so good is he’s posting by far the best contact numbers of his career, and when he does get wood on the ball, he’s hitting the bejeezus out of it.

So far this year, Mountcastle is posting a career-low strikeout rate and a career-high contact rate (by a huge margin). On pitches in the zone, he’s making contact 87.6% of the time, which is almost 10 percentage points better than last year. In 2022, his in-zone contact rate was 114th out of 130 qualified hitters. (One spot ahead of Javier Báez, if you were curious what level of swing-and-miss we were dealing with.) This season, it’s 37th out of 179.

In addition to those much-improved contact numbers, Mountcastle is in the 93rd percentile in average exit velocity, the 88th percentile in hard-hit rate, and the 94th percentile in xSLG. So is he getting unlucky, or is there a Mountcastle-shaped hole in xwOBA?

The reason expected stats are more useful as an aggregate measure than raw exit velocity is the fact that not all batted balls are created equal. A 100 mph fly ball has a pretty good chance of becoming a home run, while a 100 mph groundball has a pretty good chance of becoming a double play. Grounders generate a higher batting average than fly balls, but far fewer extra-base hits, while line drives are the most productive type of batted ball in general.

The case for Mountcastle having bad luck can be summed up in two quick stats, after which I’m going to dump a bunch of tables on you. (All numbers from this point forward are current through Monday.)

First, the league-wide batting average on line drives is .701. Mountcastle is hitting .474 on liners, which is 155th out of 161 batters with at least 10 line drives this season. That’s ludicrous. I didn’t know it was possible to hit under .500 on line drives. Second, Mountcastle has 10 batted balls this year that were hit in the air (i.e. a line drive or a fly ball) at 100 mph or more, and turned into outs. That’s tied for the most in baseball this season.

Just as expected stats are more informative than exit velocity because they incorporate launch angle, they do leave something to be desired because they don’t tell you what direction the ball was hit. Sometimes that doesn’t matter — a line drive is a probable hit wherever it goes — and sometimes it matters a lot.

Here, you can see every batted ball hit in the majors this year, sorted by direction (pull, center, opposite) and type (line drive, groundball, fly ball), giving us nine buckets. The number in each cell is the percentage of total batted balls that fell into a certain bucket:

Now, here are Mountcastle’s 72 batted balls so far this season, sorted into the same buckets:

So Mountcastle is hitting more line drives than the rest of the league, which is good. And he’s not pulling the ball, which is good in some circumstances and bad in others. Here’s the league-wide wOBA on batted balls for each direction. The buckets in which Mountcastle is hitting a higher percentage of batted balls than the league are filled in red, while buckets where the league is hitting more frequently than Mountcastle are filled in blue:

Mountcastle is filling up the most profitable batted ball buckets, with two exceptions: First, pulled line drive, which doesn’t matter. Mountcastle has a line drive rate of 26.4% to the league’s 20.4%. If he’s hitting almost a third more line drives than league average, nobody cares what direction they’re going in. Besides, Mountcastle has hit so few balls in play that the difference between beating the league average to that side and not is one hit.

The second batted ball type where the league is beating Mountcastle is pulled fly balls, which matters a lot.

Form a mental image, if you will, of a fly ball hit to the pull side, and another of a fly ball hit to the opposite field. The former is going back, back, back to the track; the latter is dropping into an outfielder’s glove 40 feet short of the fence. The league-wide HR/FB rate on pulled fly balls is 30.2%; to the opposite field, it’s 4.0%. Pulling the ball in the air instead of hitting it the other way adds an additional 257 points of batting average and 360 points of wRC+.

Mountcastle is hitting plenty of balls in the air, but he’s only pulled three fly balls so far this season. Two of those, incidentally, became home runs. So he should hit more of those, I guess.

Other than that, it’s hard to see much of anything Mountcastle could improve, strictly in terms of his batted ball profile. All he has to do is wait for his luck to change, and he’ll be the best hitter with a sub-3% walk rate of all time.