Here’s an advertisement I saw while reading an article earlier this morning:

I know how internet advertising works. I know it doesn’t matter that I saw that ad while reading an article that had nothing to do with sports. The internet knows I spend a lot of time on baseball websites. Hence, a baseball ad. But the specific ad itself doesn’t know that I’ve been interested in Eric Thames. That ad was prepped with Thames in the middle of it. It wasn’t prepped before the start of the season — it wouldn’t have made sense to feature Thames, or really any Brewer. This ad is a reflection of how well Thames started the year. It’s a reflection of how quickly he achieved broad recognition. Eric Thames was selected to help promote MLB.tv. Not Mike Trout. Not Bryce Harper. Eric Thames.

Thames’ start was absolutely incredible. He hit the ground sprinting, and I’m sure you remember all the coverage he was given. He was, and still is, a heck of a story. The Brewers are still happy to have him. But it’s worth pointing out that Thames hasn’t been the same. For whatever reason, he’s slipped into a slump.

Thames missed a few games in the middle of May. We’ll come back to that later. For now, that makes for a convenient time to split Thames’ season into approximate halves. In this table, Thames leading up to those days, and Thames ever since those days.

Eric Thames’ 2017 Split PA wRC+ K% Contact% Z-Contact% O-Swing% EV xwOBA Through 5/14 154 183 23% 74% 83% 18% 88.4 0.396 Since 5/18 123 97 32% 64% 69% 28% 86.2 0.305 SOURCE: Baseball Savant

His wRC+ has been cut almost in half. Thames’ strikeouts have gone up, and that’s been fueled by a considerable drop in contact rate. Thames, also, has gone out of the zone more often, and according to the Statcast information at Baseball Savant, Thames has hit the ball a little weaker, on average. That last columns refers to expected wOBA, which is a wOBA estimate based on strikeouts, walks, and Statcast batted-ball data. That column supports the idea we’re not just talking about the vagaries of luck. Thames has dropped from right around .400 to right around .300. That doesn’t happen by chance.

As we dig in, let’s take a look at an at-bat between Thames and Juan Nicasio, from Tuesday. The at-bat lasted three pitches. Here’s the first:

Here’s the second:

And here’s the third:

Nicasio throws legitimate gas. He’s a good pitcher, who gets his strikeouts. But that’s Thames just getting blown away, three pitches in a row. It’s worth reflecting on Thames’ first home run of the season:

The slump seems to be most closely tied to hard pitches. Following the lead of Brooks Baseball, I’ll consider hard pitches to be fastballs and cutters. Through May 14, against hard pitches, Thames had 15 strikeouts and eight home runs. Since May 18, against hard pitches, he’s at 28 and two, respectively. There are hints that opponents might be noticing:

That isn’t very dramatic. That shows a gentle rise, that might just self-correct. But let me show you a similar plot, this time highlighting Thames’ run values.

Early on, Thames was one of the best hard-pitch hitters in the league. It didn’t look like he’d have a difficult time readjusting after leaving South Korea. More recently, Thames has been one of the worst hard-pitch hitters in the league. His run values have dropped precipitously. To look at something else: through May 14, Thames’ contact rate against hard pitches ranked in the 30th percentile. Nothing great, but also nothing horrible. Since May 18, his contact rate against hard pitches has ranked in the 1st percentile. Only two hitters have made less contact, and this largely helps to explain the drop in Thames’ Z-Contact%. He’s been swinging through hard pitches, and hard pitches are frequently thrown in the zone. If you can’t make consistent in-zone contact, you’re going to get yourself in a whole lot of trouble.

Now, a few things. Even since May 18, Thames has been basically a league-average hitter. He’s by no means been terrible, so the Brewers have gotten by. He’s still popped his share of home runs. And, I said we’d come back to the missed games. A few weeks into the year, Thames developed a tight hamstring. Then he had to miss a few days on account of strep throat. Thames was in pain, and he was sick. It makes sense his swing might’ve been affected for the worse. It makes sense he might’ve lost some timing or energy. Even if he feels totally healthy now, he has to get himself back up to speed. You can’t just flip a switch.

So this could be simply a blip. And I don’t want to be too hasty to credit opposing pitchers for making the necessary adjustments, because Thames hasn’t been pitched that differently. Heaven knows he was obliterating heat when he saw it in April. Thames has developed a hole in his swing, but it seemingly came out of nowhere, and he could close it up today or tomorrow. His swing is still quick, and his eye is still good.

But something, at least, has been going on with Eric Thames. Whether because of the hamstring, the illness, or something else, Thames has become vulnerable against decent velocity. He’s started to see more velocity in June, and he continues to swing and miss. The Eric Thames that excited the country blended discipline, contact, and power. Those skills have deteriorated, and Thames needs to find a way to bring them back. It’s pretty fundamental — good hitters need to be able to hit strikes. Thames hasn’t hit the strikes that he used to.