Vegas Watch

It's May 11th, and Chipper Jones currently has a .400 batting average. This has inspired some discussion about whether Chipper can hit .400 for the entire season. Well, it's obviously a possibility, but how unlikely is it?

The first thing to do here is to figure out Chipper's true talent level. He's hitting .400 at the moment, but it's certainly lower than that. Various projections had him between .294 and .318
in the preseason. PECOTA expected him to hit .316. I'm going to use that, and incorporate his current .400 BA over 148 PAs (as Tango describes here) to arrive at an expected BA of .32677 going forwards.*

The next thing is to figure out is how many at-bats he'll end up with. This is very important- it's a lot easier to hit .400 over 10 ABs than over 1000. Before the season started, PECOTA expected him to have 600 PAs. Incorporating the 148 PAs he's already accumulated over his team's first 35 games, we should expect 618 PAs at this point- that'd mean about 525 ABs. I'll also include situations where he has 518, 568, and 668 PAs, since the probabilities will be different for each.

Using this information, here are the chances that he hits .400 given each number of PAs:

Ideally, he'd like to get exactly 502 PAs, which is the minimum required to qualify for the batting title. If he did that, his odds would be 1 in 225. As those PAs go up, it gets very unlikely, very quickly. Weighting the 618 PA scenario as 40%, and the other three as 10%, 30%, and 20%, respectively, we come to odds of 1 in 546.

If he keeps this up (unlikely), some enterprising gambling site will probably offer odds on whether he'll hit .400. I'll be interested to see what they are, although I'm sure they'll be absolutely terrible. If they were listed now, I think they'd probably be along the lines of 50:1, maybe even 25:1.

I think this is because it's a rate stat, rather than a counting stat. What I mean is that he's hitting .400 now, so at first glance it seems at least somewhat likely that he'll keep it up. Contrast this with a guy who gets off to a hot start (20 HRs) hitting 70 HRs- he's still got a long way to go. For a guy hitting .400 with 20 HRs at this point in the season, even if it's more likely that he hits 70 HRs, it'll seem more likely, to the average person, that he'll hit .400, since he "just" has to keep up his pace, rather than more than triple his HR total.

The ideal candidate would walk a ridiculous amount. In 2004, Bonds had 617 PAs, so he easily qualified for the batting title, but only 373 ABs. He probably had a better chance of hitting .400 that year than anyone else in recent memory- he ended up at .362.

The closest thing to that today is Pujols. He's walked in 21.7% of his plate appearances so far. In theory, he could end up with the requisite 502 PAs, but only about 385 ABs. He's off to a very good start himself, hitting .348 through 172 PAs. If we figure his true talent level at .335 (which includes the boost explained below), he'd have a 1 in 694 chance of hitting .400 if he ended up with exactly 502 PAs this year. Lower than Chipper, but only because he's currently hitting 52 points lower. Point being, the person most likely to hit .400 in 2009 is probably Pujols, both because of all the walks and his historically high BAs.

*There's a reason I'm using such an optimistic prediction. Since we only care whether he reaches such an extreme milestone or not, his BA for the purposes of figuring out whether he'll hit .400 or not is higher than his expected BA for the rest of the year in all situations. For example, take two scenarios, one in which he hits .200 over the next two months, another in which he continues to hit .400. To determine his BA over the last two months of the year, the first example is irrelevant- if he's hitting .285 on July 10, he is not going to hit .400, so we don't care. However, if he's hitting .400 on July 10,he still has a shot. So, we care about the .200 but not the .400, which skews his batting average for this exercise upwards. Thus the optimistic .32677 BA.

Photo: FanIQ

Also: Forget What You Think You Know [The Money Line Journal]