Are you familiar with Voros’ Law? Voros McCracken, best known for his work in DIPS theory, came up with the following maxim, dubbed Voros’ Law: Any major league hitter can hit just about anything in 60 at-bats. Intuitively, all baseball fans understand this on some level. Roughly speaking, 60 ABs is about two weeks for a full-time player. Longtime readers know of my six-week hot streak premise. So, if stiffs can perform unusually well in six weeks, it stands to reason they could do even better in AVG over just a two-week period.
To illustrate Voros’ Law, let’s use famously weak-hitting infielder Mario Mendoza, the man for whom the “Mendoza Line” is named. Mendoza was hardly the worst hitter to ever appear in MLB. But when George Brett tags you with a line, well, it kind of sticks. Anyway, from 1977-1979, Mendoza twice finished with just below a .200 AVG, hitting .198 in both 1977 and 1979, leading Brett to name batting .200 the Mendoza Line.
Using the Baseball-Reference span finder, a search was done for single-season spans of 20 games with at least 60 ABs for Mendoza’s career, which lasted from 1974-1982, although he only played 12 games in his final season. We ended up with 82 different spans which met the criteria. And in those 82 spans, the weak-hitting Mendoza posted AVGs ranging from .164 to .383 – yes, that’s not a misprint. From 5/24-6/16 in 1980, Mendoza went 23-60 for a .383 AVG.
That same year, Brett captured the nation’s attention with his run at a .400 AVG, something that hadn’t been accomplished in the majors in nearly 40 years at that time. Brett finished with a .390 AVG that season. So, for two weeks, Mendoza did a pretty good imitation of one of the best hitters of his generation in his signature season. That means that, yes, any hitter can hit just about anything in 60 ABs.
Back when Mendoza was active, AVG was thought to be one of the best – if not the best – way to evaluate hitters. Now, we know better and understand that there are more than a few superior ways to rate offensive performance. For simplicity’s sake, let’s use OPS. And Voros’ Law applies just as much to OPS as it does to AVG. And to illustrate that, let’s use Starling Marte.
Instead of using 20 games and 60 ABs as our parameters, like we did with Mendoza, let’s use 41 games, since that’s how many Marte has played so far here in 2023. There were 813 different spans in a single season of 41 games for Marte. His best was a 1.027 OPS from 8/9 to 9/24 in 2014. And his worst is the .577 mark he has right now in 2023.
If we used the same 20-game, 60-AB criteria that we used with Mendoza, we might have gotten a much-wider array of outcomes. Still a range of .450 points of OPS is hardly tiny. Which prompts the question: Is 41 games still a small enough sample that any hitter can produce any OPS, including a stretch that would look at home with an average Mendoza sample or an average Brett sample?
The quick answer to that question is yes, a 41-game sample is still small. But just because it’s small doesn’t mean it’s not worrisome. And the next question is: How significant is Marte’s current .577 OPS?
Early in the season, everyone wants to throw out the phrase, “Small Sample!” to any numbers one cites. And it’s not that they’re wrong, even if they can be somewhat obnoxious in their delivery. But it’s important to look past perceived obnoxiousness and look at the real issue. When does a sample size go from small to relevant?
It’s different for different metrics.
Several years ago, statistician Russell Carleton, who later worked for the Mets in 2019, calculated the total number of PA you need for a given statistic to reach the point where the correlation between that sample and another sample of the same size is 0.7 (i.e. R^2 of .49). That came to be popularly known as the point of “stabilization,” a term that Carleton didn’t like. He calculated this for numerous stats and the stabilization point is all over the map. Unfortunately – or fortunately, depending on your point of view – it takes longer than Marte’s current stretch for either OBP or SLG to stabilize.
But one of the quicker metrics to hit that stabilization point is ISO. Carleton found that ISO reached that 0.7 point of correlation at 160 ABs. Marte has logged 147 ABs so far in 2023. And in those 147 ABs, he has just five extra-base hits, for a .048 ISO, which is terrible. Last year, Marte had a .176 ISO. All that means that we’re very close to the point where we can officially be concerned about Marte’s power. Sure, it wouldn’t be a surprise if he had positive regression with his singles. And while those singles would boost his SLG some – thus why it takes longer for SLG to reach that 0.7 mark – we should probably eliminate any thought that he’s going to match last year’s ISO.
Forget a .176 ISO – a better question now is if Marte can turn things around and produce a triple-digit ISO by the end of 2023.
Every now and then, Marte makes good contact with the ball. But as what happens frequently when a player is slumping, those balls are mostly going foul. And at least as many times as he makes that good contact, we see a swing that looks like one you’d expect from a 9th-place hitter on a Little League team, rather than a two-time All-Star. Here are two videos courtesy of Baseball Savant. This first one is from May 16th:
And here’s another ugly one a day later
Marte actually got off to a good start this year. In his first 13 games, he had a .296/.404/.455 line in 54 PA. Since then, he’s gone 110 PA without an extra-base hit and has a dismal .452 OPS. Yet he continues to play nearly every day.
We saw last year in September how the Mets’ offense struggled while Marte was on the IL. And for the most part here in 2023, we’ve seen the offense flounder with Marte struggling to the degree he has. It makes you wonder if Marte is playing thru an injury. We know he had offseason surgery both for core muscle and groin issues. Then he was hit in the head while stealing a base early this season. And he had to miss a game recently after being hit on the hand with a pitch. It wouldn’t be a surprise if various injuries played a role in his tough results.
If that’s the case, then the Mets should put him on the IL and have him do an injury-rehab stint in the minors. Even if Marte is healthy, the injury rehab allows him to go to the minors in a face-saving move. He can look to get his swing right against lesser pitchers, hopefully giving him the confidence to rebound once he returns to the majors.
And it allows the Mets to call up Ronny Mauricio, while still giving Tommy Pham extra time to show he’s worth a roster spot. Actually, Pham’s production to date – HR boosted as it is – makes him roster-worthy. The real question is if Mauricio can produce enough to make Pham expendable. If the Mets send Marte out with an injury rehab, they would have around three weeks for Mauricio to show his stuff. That may not be enough time to make an informed decision. But it’s better than having him stuck in the minors while Marte does his best Mendoza imitation.
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