Why is Lars Nootbaar’s BABIP so low?

Lars Nootbaar has struggled in September. For people who follow the Cardinals everyday, this probably isn’t news. He was a leadoff hitter at the beginning of the month and now tends to bat towards the back of the lineup. He also used to start against lefties. He isn’t anymore. After going 1 for 4 with a HR and a BB on September 2nd, he has a 12 wRC+ in the rest of September. His offensive performance went a long way towards giving the Cardinals the best offense in the 2nd half, and its absence is partly why the offense has been not the best lately.

He seems to be suffering from two issues: strikeouts and infield flyouts. These are basically the worst two outcomes as a batter. He has a strikeout rate of 26.7% and 27.3% of the balls he hits in the air were infield flyballs. Out of 45 plate appearances, 33.3% of plate appearances were essentially guaranteed outs.

And yet, the main culprit for why he has a 12 wRC+ since September 3rd is a .080 BABIP, far below a reasonable expectation for just about any MLB hitter. He is still walking, so the approach appears to still be there. He has a 13.3 BB% in this span. That’s why I personally love having guys who walk on the team, because you still believe they might get on base when they are slumping because they will take a walk.

This recent stretch has pushed his season BABIP all the way down to .237. Despite that BABIP, he still has a 119 wRC+ on the year. That is not typically a combination you will see 298 plate appearances into a season. Small sample? Sure. Halfway through a full season. Most 119 wRC+ hitters or better will not have .237 BABIPs and if they do, usually they are considered elite hitters.

One thing about his line did catch me eye though: he has a .339 xwOBA. Why did this catch my eye? Well, he has a .335 wOBA. Pretty much the same. I don’t know if yesterday’s game will affect those numbers, but probably not much if they do. What this means essentially is that, by Statcast, his wOBA is deserved. The .237 BABIP is, hypothetically, not unlucky.

This confuses me greatly. I am by no means suggesting someone could not have a deserved BABIP of .237, I am however struggling to accept that Lars Nootbaar would be that someone. Now, I am not going to quibble with whatever method Statcast used to get to that xwOBA. Maybe he has hit the ball hard to areas where fielders typically are at an unusual rate or something. Maybe there is something in his batting profile. I can’t find it though.

Lars Nootbaar hits the ball very hard. Harder hit balls haver higher BABIPs. A hard hit ground ball is the next best thing to a line drive followed by a hard hit flyball. Among hitters with at least 250 plate appearances, Nootbaar ranks 33rd among hitters in average exit velocity of 91.4. His max exit velocity is in the 79th percentile. He clearly hits the ball harder than most major leaguers.

He is also reasonably fast. His sprint speed is in the 75th percentile. More importantly, he is left-handed and left-handed batters have a huge advantage in infield hits. Despite ranking 146th in sprint speed (which as I said, was 75th percentile), Nootbaar is 81st in average time from home plate to first plate.

So he’s fast and he hits the ball hard. Is there something in his batting profile? Well, typically flyball hitters will have a lower BABIP because if a flyball isn’t leaving the park, it’s an out a lot of the time. But Nootbaar isn’t a flyball hitter really. He has hit a flyball 37.5% of the time he’s put a ball in play. That’s nearly exactly dead average. 69th out of 136 qualified hitters. A larger portion of those are infield flyballs than most, but that doesn’t fully explain it either.

I can’t verify these numbers, but I found a fantasy site that lists BABIP based on contact quality. This does get a bit tricky because I can’t distinguish between a hard hit flyball and a softly hit flyball which have very different expected BABIPs (.078 versus .235). The line drives is a bit easier to square away since it’s a difference of .719 and .632. So yeah hit line drives kids. Doesn’t matter if it’s soft or.... I’m not finishing that sentence.

Let’s play around with these figures a little. So Nootbaar has a very high exit velocity which means you can safely assume a lot of the balls in play are on the higher end of expected BABIP. We have three categories. Hard hit, medium hit, soft hit. Let’s just take the averages and know that Nootbaar should probably rank higher because he hits the ball harder.

He’s hit 82 groundballs, which should results in 19 hits. 69 flyballs minus the 12 homers should result in 6 and half hits, but since Nootbaar hits more infield flyballs, we’ll say 6. And 33 line drives should result in 22 hits. That would give him 47 hits. 47 hits coupled with the 12 homers would give him 59 hits on the year. He has 54 hits on the year.

That was assuming Nootbaar was an average hitter. Theoretically, he hits the ball harder and should have a higher expected amount of hits than that. And yet his xwOBA says he’s not actually getting unlucky. Here’s the really strange part to me. Statcast has Nootbaar’s xBA at .238, which is better than his current .219 average (although his 0-2 yesterday is not included in that xBA). His xSLUG however is way lower at just .376. His actual slugging is at .429.

I know what you’re thinking, because I thought the same: surely it’s homers that are the discrepancies. Nootbaar is hitting a couple homers that probably shouldn’t be homers. Except no. Nootbaar has 12 homers on the year and his xHR is 12.7. The numbers say he has the right number of homers (0.7 more technically, but 0.7 HRs would be difficult to do). He’d have less homers at five stadiums, 12 homers at seven stadiums (including Busch), and more than 12 in the rest, including as high as 15 homers. The homers aren’t fluky.

The only reason I answer I can conjure is the infield flyballs. He does hit a lot of them. 13% of his classified flyballs are infield flyballs. I don’t think this fully explains it still, because we’re relying on a grand total of six flyballs to become hits for that expected output, but the same issue plagues Nolan Arenado, who absolutely destroys his xwOBA every year. He has a career xwOBA of .341 compared to a wOBA of .377. Some of that is Coors, but he’s outperformed it both years in St. Louis by a decent amount.

But Arenado does hit a lot of infield flyballs. He has a career IFFB% of 12.6% and that’s only because he didn’t hit that many infield flyballs earlier in his career. It’s been 13.1% or higher every year since 2019. And to be fair, Arenado does actually have a relatively low BABIP. He has a career BABIP of .293 which doesn’t seem low, but most of his PAs were at Coors and I promise you that’s very low for Coors. 22 hitters batted at least 1,000 times from 2010 to 2022. Arenado is above 36-year-old and older seasons of Todd Helton, career 56 wRC+ hitter Tony Wolters and Chris Iannetta with a career BABIP of .279. That’s it. Even Ian Desmond had a higher BABIP.

Of course, Arenado and Nootbaar are very different hitters. Arenado is very much a flyball hitter to the extreme. Nootbaar isn’t. At Nootbaar’s current pace, he would hit 17 infield flyballs with 577 plate appearances, Arenado’s plate appearance total. Arenado has 40 infield flyballs this year. He is hitting them at a higher rate (17.4% plus he hit one yesterday), but more importantly he hits a lot more flyballs. Mainly I just don’t think Nootbaar’s infield flyballs would really derail his BABIP this much.

In conclusion, I still cannot think of a single reason why his BABIP is so low. Except for sometimes in baseball, you have a .237 BABIP over a random 300 PA sample. But in that instance, we would expect a higher BABIP going forward. Maybe you knock a few points off because of the infield flyballs, but that’s still like .285 or .290. He simply hits the ball too hard to not expect it to turn around.

He probably won’t walk this much going forward, maybe he’ll strike out more, some part of his game might get worse while we see a higher BABIP. but... the benchmark so far here is a 119 wRC+. It sure feels like the BABIP difference is more massive than declines in other parts of his game from where I’m sitting. Is it possible Nootbaar can be even better than he’s been? I am excited to find out.