Mookie Betts is on an historic pace but can he keep it up?

NEW YORK, NY – MAY 10: Mookie Betts #50 of the Boston Red Sox in action against the New York Yankees at Yankee Stadium on May 10, 2018, in the Bronx borough of New York City. Boston Red Sox defeated the New York Yankees 5-4. (Photo by Mike Stobe/Getty Images) /

Mookie Betts has been the brightest star for the Boston Red Sox despite J.D. Martinez living up to every bit of the hype. Just how good has he been?

Mookie Betts is off to his best start ever. That’s not news, of course, but it’s certainly noteworthy in a number of ways. As I write this, he came into this evening’s game with the league lead in wRC+, OPS+ and fWAR, tied for 1st in TB, in a six-way tie for the most HR at 13, and 3rd in rWAR.

If the MVP were voted on today, he’d have as good a chance as anyone of winning. But how does this start to look when compared against more than his 2018 contemporaries?

Whether we look at his 203 wRC+ or 201 OPS+, he’s hitting the absolute snot out of the ball. In order to look at individual seasons going all the way back to the beginning of baseball’s history, we’re going to use the Baseball Reference Play Index. To start, let’s see where his full-season rWAR pace would leave him, and then compare that to the best seasons all time.

A 162 game season isn’t realistic since Mookie Betts has already had some days off. Of the 44 games the team has played, he has appeared in 39. So his 162 game pace is 10.9 rWAR — when we adjust for what he’s actually on pace to play that 162 drops to 144 games. So 2.9 rWAR over 39 games becomes 10.7 by the end of the year. That would be, by far, his best season to date.

Where does it end up all time?

The Play Index says that there have been only 23 seasons in the history of the game in which a hitter produced 10.7 rWAR or more. Mookie would end up tied with Ty Cobb at the back of that list. Seven players appear more than once meaning only 13 players have achieved the feat. Babe Ruth did it six times in case you were wondering. Ted Williams appears once. Mike Trout’s best season produced 10.5 rWAR, though he’s currently on pace for 13.1. But who’s counting?

What if he keeps up the pace with his 201 OPS+? That one isn’t quite so rare, with 57 seasons matching the criteria. Still impressive, but we start to see some less elite names cracking the list. When we look at TB, Mookie is on pace for 406 by season’s end. There have been just 22 seasons which have seen a player amass as many TB.

What happens when we combine all three criteria? Now it’s getting interesting. Only four seasons in the history of the game have produced 10.7 rWAR, a 201 or higher OPS+ and 406 TB. Two of them were by Babe Ruth, one by Barry Bonds and the last by Lou Gehrig. If Mookie Betts keeps up this pace, he will find himself in a truly historic company.

The odds are against him, but…

If we are looking for signs that Mookie Betts might have an all-time great season we can start with Brls/PA. At 14.8, he is second in the majors to just J.D. Martinez. Using his launch angles and exit velocities, we can see that his expected slugging is somehow higher than his actual slugging of .734. It sits at .823. His current wOBA is .471. The expected version? It’s at .523 (league average is about .320).

And finally, Betts has his hard hit percentage up to 50%. He’s making hard contact half the time he puts the ball into play. That’s nuts and puts his barrel percentage at 19.2%.

We can use that figure to guess what his season might end up looking like. If 19.2% of his balls in play are Barrels, that means 19.2% of his balls in play have a BA of .500 and a SLG of 1.500. Since he has a batted ball in 73% of his PA, we can extrapolate a full season out that and estimate how many Barrels he’ll have on the season.

More from Call to the Pen

At 700 PA he’d have around 511 batted balls and about 98 Barrels. That’s 49 hits from just the Barrels. With his career BA going forward he’d finish with 215 hits on the season. With a 10.2% walk rate, we can add 71 walks and set his OBP at something around .409 and his BA at about .342. Using his xSLG to finish his triple slash line we’re looking at .342/.409/.823 for an OPS of 1.231 which would be 14th best all time.

Let’s get a little less silly.

Of course, that’s relying on his .823 xSLG which would be 4th highest ever. So let’s regress that to his SLG if he keeps up the pace for that 406 TB. Now we have .646 instead of .823 and an OPS of 1.055. That leaves us with 186 seasons matching or exceeding his projection. No longer historically great, but it’s starting to feel much more achievable.

All this fun with the numbers is, ultimately, meaningless. The chances that Mookie Betts finishes the season as strongly as he’s started it are slim. The elite company he’s on pace to finish with should be enough to tell us that he’s going to cool off eventually.

Of course, with his more realistic projection still being north of a 1.000 OPS, we could well be in for a career year. One that surpasses his 2016 campaign. And Red Sox fans should be really happy about that if that’s “all” he does.

Next: Robinson Cano steroid/HOF debate

Oh, and despite the ridiculous pace he is on coming into tonight’s game, he had three hits and three stolen bases tonight so that WAR and his OPS+ are going to inch up by the time you are reading this. It seems he isn’t quite done setting those expectations at a mind-boggling level.

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