Mookie Betts and RBI Rates

Following the five home runs he hit in the last three Red Sox games entering Wednesday, Mookie Betts has quickly joined the AL MVP race. Mike Trout, Josh Donaldson, Jose Altuve, and Betts are the only four hitters in baseball with at least 6.0 WAR so far this season. That race may come down to contextual factors beyond his control, such as whether the Red Sox makes the playoffs, but however it unfolds, Betts has an even stronger chance of landing the fantasy MVP, ignoring draft positions. His combination of 28 home runs and 18 stolen bases is so rare in today’s game. Trout and Wil Myers are the only other players threatening the 30-20 club, and they’re both five home runs short of Betts at the moment.

To a certain extent, all of this is surprising because, one, Betts had never been an MVP candidate before and, two, he’s only 5’9 and 180 lbs., which not exactly the standard build of a 30-plus home run hitter. However, Betts did go 18-21 last season and is still just 23 years old. He already showed the speed, and it wasn’t unthinkable that he’d develop more power. So, as crazy as it sounds, Betts’ impressive home run and stolen base totals are not the No. 1 surprise of his fantasy season. It’s actually his RBI total.

With 89 RBI, Betts is currently fifth in baseball. His teammate David Ortiz is third with 92, and given the gap in offensive productivity between the Red Sox and the rest of the teams in baseball, it is no wonder that a handful of Red Sox were near the top of the list. But in Betts’ case, it is still pretty amazing. Until about a week ago, Betts was primarily used as the team’s leadoff hitter. 108 of his 114 starts have come at the top of the order. When you focus only on hitters who start most of the games in the leadoff spot, Betts is well ahead of the field in RBI.

Again, the Red Sox offense has a lot to do with this, but Betts himself has taken amazing advantage of his opportunities to drive in runs. Betts has come to the plate with a runner in scoring position (RISP) 130 times. That means that his rate of RBI produced per RISP is 68.5 percent, which is 3.1 percent better than Jay Bruce in second place and more than 10.0 percent higher than all but seven players. Similarly, Betts has an RBI for every 32.1 percent of the runners who have been on base for him, which is 2.2 percent clear of the field that his tightly bunched behind him.

Betts may have been somewhat fortunate in having as many RBI opportunities as he’s had, but his 130 runners in scoring position hardly measures up to the leaders like Carlos Correa (199), Anthony Rizzo (198), and Albert Pujols (187). Meanwhile, Betts hasn’t performed demonstrably better with runners on base (.322 batting average) than he has with the bases empty (.310). Coco Crisp has set that standard with a .365 average with runners on versus a .187 average with the bases empty. More important names on this list for fantasy players include Adam Duvall, Mark Trumbo, Pujols, and Ortiz.

In the case of players like Ortiz and Pujols, the fact that men are on base might legitimately be expected to help their batting average since baserunners can act as a defensive shift deterrent. Still, lack of statistical evidence for sustained clutch hitting suggests that the players on this leaderboard could see their pace of RBI slow down over the rest of this season and into next season.

In contrast, the trailers can expect their RBI pace to improve.

If he continues his pace and health, Betts should reach 120 RBI despite spending the bulk of the season as a leadoff hitter. That sounds crazy, but his production with men on base has not dramatically outpaced his production with the bases empty, and so he is not a clear candidate for regression of his RBI pace. Instead, Betts could potentially even increase his pace of RBI if he continues to bat in the heart of the Red Sox order, which he has over the past week. That could cost him a few stolen bases down the stretch run, but I think fantasy owners will be fairly content with a .315-35-120-120-22 season.