With the Major League Baseball regular season nearly six weeks old, there are a few statistical anomalies that appear to be unsustainable.

Justin Verlander and Michael Wacha cannot possibly maintain their historically great marks in batting average against and baserunners stranded, right? Just like Marcus Semien can't possibly go straight from a 45-home run season to a great big doughnut in that category?

Regression to the mean is coming.

Using a variety of metrics like BABIP, xFIP and SIERA to compare a player's production to both the current league averages and his previous career marks, we've pinpointed eight players who appear destined to get either substantially better or worse over the rest of the season—two pitchers and two batters in each direction. We'll oscillate between expected positive and negative regression.

To wrap things up, we'll also highlight the one team most likely to start trending in each direction.

Unless otherwise noted, statistics are current through the start of play on Monday, May 16.


Positive Regression: Marcus Semien, Texas Rangers

2022 Stats: .157/.216/.213, 0 HR

2019-21 Stats: .268/.346/.509, 37 HR per 162 games

Before we begin, let's throw out a big disclaimer that will apply to all of our choices for positive regression: We have no way of knowing if these guys are quietly battling through some sort of injury/affliction. Case in point, we harped on Eddie Rosario's brutal start to the season for Atlanta only to find out he was dealing with eye swelling that necessitated surgery.

In other words, we're assuming that bad luck will turn around, but we acknowledge that these disappointing starts might be more than just poor luck.

Having said that, Marcus Semien is not hitting the ball like he used to.

Per FanGraphs, the exit velocity on Semien's batted balls is a full five miles per hour below what it was last season, falling from a career high of 89.7 to a career-worst 84.7. His line-drive rate (14.4 percent) is much worse than his career average (20.7), as is his soft-hit percentage (25.0 percent this year; 16.8 percent career).

Because of that, his batting average on balls in play (BABIP) is dreadfully low (.192), both by his career standards (.288) and compared to the 2022 league average (.284).

But he is at least putting balls in play. He's striking out in 18.0 percent of plate appearances after back-to-back seasons above 20 percent. He just seems to be pressing, seeing fewer pitches per plate appearance (3.65) than he typically does (4.04) and not capitalizing on the fastballs that he mashed with regularity in both 2019 and 2021.

Sooner or later, he's going to get off the schneid and finally hit his first home run in a Rangers uniform, and I suspect that will open the floodgates for a hot streak. One simply doesn't finish top-three in the MVP vote in two out of three seasons and suddenly forget how to hit a baseball.


Negative Regression: Justin Verlander, Houston Astros

2022 Stats: 1.38 ERA, 0.68 WHIP, 8.1 K/9

2019-21 Stats: 2.59 ERA, 0.80 WHIP, 12.1 K/9

It is wild that Justin Verlander is pitching this well at 39 years old, fresh off a Tommy John surgery that limited him to just one appearance over the past two seasons. But, to be clear, this selection has nothing to do with Father Time and everything to do with unsustainable metrics.

For starters, there's the .168 BABIP. In the past half century, no qualified starter has finished a season with a BABIP below .207—though Verlander did have a sensational .218 mark while winning the 2019 AL Cy Young.

Not only has Verlander been fortunate in that regard, but he has also been especially good/lucky when it comes to stranding runners. He currently has a left-on-base percentage of 94.7, which again would be the best in recent history by a wide margin. Shane Bieber's 91.1 mark in 2020 was the best of the past 50 years; Robbie Ray's 90.1 mark last year was the best among seasons with more than 60 games played.

And let's be sure to point out that he's hitting these unsustainable marks with a drastically lower strikeout rate than usual, which means he has been historically lucky on balls in play while also allowing more balls to be put in play. So, when the worm turns and balls in play start landing for hits, things could snowball.