Kauffman Stadium home run suppression is making it harder for Bobby Witt Jr. to make his case.
Before I start down this path, just know that Aaron Judge is having an unbelievable season the likes of which are rarely seen. If Bobby Witt Jr. ends up losing the MVP to a guy slugging over .700, it is not the end of the world. Still, Bobby is also having a historic season, especially for a shortstop, and if he ends up second some of the blame could be put on the home field in Kansas City.
Barring injury or some weird slump, Witt Jr. is going to have a 10+ WAR season. He already has 8.8 fWAR and 8.3 bWAR with about a fourth of the season to go. Since 1930 there have only been 32 seasons of 10 or more fWAR, so it happens on average once every three to four years. This year both Witt and Judge are likely to. This is rarefied air only occupied by the likes of Mike Trout, Babe Ruth, Ted Williams, and such - almost all who reach this mark are all-time greats.
Bobby Witt would be only the fourth-ever shortstop on the list of 10+ fWAR seasons along with 1948 Lou Boudreau, 1991 Cal Ripken Jr., and 2002 Alex Rodriguez. He is in the top ten all-time for slugging for a shortstop season right now and almost top ten all-time for wRC+. While doing that he may end up leading the majors in defensive runs saved. He is having a top tier season and it could be even better, were it not for Kauffman Stadium.
According to Baseball Savant xHR-HR, where you take expected home runs minus actual, Bobby Witt Jr. is missing the most home runs in the league. His 25 should be more like 29.8 in expectation based on the balls he has hit. Even more than that, Vinnie Pasquantino is 7th on the list and Hunter Renfroe 11th. Three of the top eleven players who have been robbed of home runs reside in Kauffman Stadium for their home games. Nelson Velazquez and Michael Massey aren’t far down the list either and they both have missed significant chunks of the season.
Based on where Witt has hit all of the balls he has hit this year, from park to park he has a possible range of expected home runs from 21 to 39! If he played in Cincinnati he would be expected to have almost reached 40 already. The 21 is Kauffman, so he has outperformed his expectation relative to his home park. The MVP discussion would be very different if he was playing in a bunch of the parks around the league. In 10 of the parks he would have expected home runs of 35 or more, so at least 10 more than he has actually hit.
Where those 10 home runs come from matters. If it is turning a harmless fly ball into a homer, that changes the numbers significantly. If it is turning doubles into home runs then the effected is muted. We also need to remember that playing outside of Kauffman would mean his triples would probably drop quite a bit as it is a very friendly park for them. KC is a net positive to offense with a park factor of 101, but its home run factor is 80 (20 percent below-average). It is above-average, and in the top five in the league, for singles, doubles, and triples.
Would adding 10 or more home runs while losing some singles, doubles, and triples help Bobby’s MVP candidacy? If he moved to a strictly average field, it would not. The extra home runs would not be able to offset the other lost hits. Doing some simple Excel models, it does look like Anaheim would benefit him greatly, and I think Fenway might make Witt look ridiculous though more for doubles and triples than home runs. Part of the problem with trying to do this analysis accurately has to do with how park factors work. For instance, the Royals triples factor is inflated due to the fact that Bobby exists to take advantage of the field. Their triples factor is usually high, but not nearly has high as this year when he is tied for second in MLB.
There are a bunch of non-park-related factors that change this calculus too. The first is Juan Soto. Aaron Judge gets to hit behind another of the top MVP candidates, while Bobby has hit second all year in the lineup with the worst lead-off production in the league. He does have some protection from behind, Vinnie’s home run on Friday was extra fun after they intentionally walked Witt. Judge has similar protection behind him, Giancarlo Stanton or Austin Wells, 750ish OPS kind of like Pasquantino. Soto is on base a ton which makes it way harder to work around Judge. Except for when they inexplicably walk Soto to get to Judge, oops. That is unlikely to ever happen again.
I may eventually run out of ways to talk about the amazing season that Bobby is having, but as of now it is taking most of my attention that isn’t directed at the playoff contenders’ wins and losses every day. Having Bobby win the MVP would be the cherry on top, but I really do not think it is going to happen because of the utterly ridiculous season Judge is having at the plate. It is too bad that Kauffman may end up playing a part in him losing out to Judge in the end, but it takes nothing away from how good he has been this year.
