What’s the deal with Steven Matz?

Like several of his peers in the Mets’ starting rotation, Steven Matz has not been nearly as good this year as he was in the past. Although his start last night in Colorado wasn’t exactly dreadful, it wasn’t very good, either, and it was the best of his past few starts by a fairly wide margin. In total, he’s sitting on a 5.50 ERA and 5.07 FIP in 52.1 innings this year. That’s a big jump from his previous major league experience, which consisted of 28 regular season starts with a 3.16 ERA and 3.44 FIP between 2015 and 2016.

Matz’s major peripherals jump off the page, as his strikeout rate is down to 6.19 per nine innings/15.6 percent. He was comfortable above eight strikeouts per nine and hovered around 23 percent in each of the past two seasons. And while his walk rate is right at his career norms, he’s given up a staggering 1.72 home runs per nine innings, a major increase from the 0.96 he averaged over the past two years.

While he had a 2.12 ERA after his start on July 3, those rate stats were not encouraging even as things were ending well for him. The strikeouts were already down, and the home runs were already up, before this recent brutal stretch that has seen him post an 11.78 ERA over the course of five starts.

Strikeouts down

This isn’t breaking news by any means, but swinging strikes—swings and misses—are crucial to generating strikeouts. So a pitcher’s swinging strike rate can help when it comes to predicting strikeout performance, and Matz has fared poorly in this regard. After putting up a good rate of 9.8 percent last year, which was a tick above the 9.5 percent league average for starting pitchers, Matz is at just 6.9 percent this year. And the league average for starting pitchers is a bit higher this year at 9.7 percent.

There hasn’t been a drastic change in velocity for Matz this year, but there are some minor differences, according to Brooks Baseball. The classifications there haven’t recorded a four-seam fastball for Matz this year, and his two-seam fastball has averaged 93.82 miles per hour, down a shade from the 94.39 he averaged last year. His changeup is up from 83.87 to 84.32, his slider is down about two miles per hour to 85.79, and his curve is virtually identical to last year’s mark at 78.67.

The abandonment of the four-seam fastball isn’t really a big deal, as Matz threw is just 12.3 percent of the time last year. What he’s dropped there, he’s made up for almost exactly with his two-seam fastball. But his offspeed mix has definitely been different. He’s thrown his curveball more than ever at 23.6 percent, and his slider usage has plummeted from 10.4 percent last year to 3.4 percent this year as he’s avoided the pitch in an effort to stay healthy. His changeup usage has ticked up slightly, as well.

Unsurprisingly, the offspeed pitches had been Matz’s best when it came to generating swinging strikes. His change, which was at 16.3 percent last year, has still been doing okay at 12.6 percent. But the slider is down from 13.9 to 7.4, while the curve is down from 10.5 to 4.2. Since has hasn’t thrown the slider often overall—and has made several starts in which he has not thrown it once—that decreased whiff rate on the pitch is not the end of the world. But what had been his second-best weapon in getting hitters to swing and miss has been greatly diminished, and no matter how much some folks like pitchers who pitch to contact, it’s harder to get good results when you’re striking out fewer batters.

Home runs up

The swings that used to be whiffs aren’t just turning into weak contact now, either. Matz has been tattooed across the three-and-a-half pitch board, with hitters capitalizing most on his two-seam fastball. And among the 321 pitchers with at least 100 batted ball events this year, Baseball Savant has Matz at the 56th-highest average exit velocity against at 88.2 miles per hour. And despite having pitched relatively few innings, he has surrendered 73 batted balls that left the bat of the opposing hitter at 95 mile per hour or higher. That ranks 130th out of those 321 pitchers.

But exit velocities really pinpoint the issue for Matz when it comes to batted ball types. On fly balls and line drives, opposing hitters have averaged an incredible 94.3 miles per hour, the 16th-highest average among that same group of pitchers. And while Matz had given up some home runs to left-handed hitters last year, the problem this year is exclusively righties. Same-handed hitters have not hit a home run against him, but opposite-handed hitters have hit them at a clip of 2.23 per nine innings.

Here’s where Matz threw his pitches against right-handed hitters last year:

Brooks Baseball

And here’s where he has thrown pitches to righties this year:

Brooks Baseball

Instead of keeping pitches up and away, both inside and outside the strike zone, Matz has thrown a lot of pitches right down the middle. Unsurprisingly, hitters don’t swing and miss nearly as often at pitches thrown down the middle of the plate as they do elsewhere.

Between his inability to stay health for a full season and the results he’s gotten this year, it’s hard to see how the Mets can go into the 2018 season with him locked into one of the five spots in their starting rotation. That doesn’t mean they should get rid of him, but barring a significant turnaround in results and two completely healthy months from now through the end of the season, it just wouldn’t be wise to pencil in even 150 innings of good pitching from Matz next year. He could accomplish all of that, but something about the way he’s pitching will have to change. What he’s done so far this year just isn’t working.