Even though his strikeout numbers fell again, everything else looked good: Only 17 relievers allowed a lower average exit velocity last year and just two managed a higher groundball rate. That last point is particularly compelling in a time when the average fly carries to the warning track and one of Max Muncy‘s dingers dented the space station. Treinen may never recapture the immortal form he wowed us with in 2018, but he doesn’t need to; the world needs set-up men, too.

In 37 innings between the regular season and playoffs, Treinen struck out 32 batters, which is below-average for a reliever, but he also walked just nine and gave up only two homers. His velocity is in the upper-90s, but the sinker that propelled him to greatness just doesn’t miss bats like it used to. When Ben Clemens wrote about the Dodgers’ signing of Treinen a year ago, he noted that the sinker wasn’t sinking in 2019 like it did in ’18.

The net result wasn’t a disastrous pitch; Treinen’s whiff rate was still among the top 10 in baseball. But much of his game was built around the ability to throw the pitch with impunity; he flooded the zone with it and his complementary four-seam fastball in all counts. In 2018, he threw 56% of his fastballs in the strike zone. When he was behind in the count, that rate spiked to 64%. Treinen threw you fastballs and dared you to do anything with it.

It’s hard to know whether he lost control or started nibbling due to his declining groundball rate, but 2019 was very different. He threw only 45% of his fastballs in the zone, and the number didn’t increase when he was behind in the count. Throw that many fastballs with that low of a zone rate — the league threw fastballs in the zone nearly 59% of the time when behind in the count — and walks are sure to follow.

That’s pretty much the Blake Treinen story. He was a one-pitch marvel who built everything off of his devastating sinker. When he couldn’t use that pitch in the same way he used to, the rest of his game couldn’t hold up. His four seam fastball is average, mainly a way of ambushing batters sitting on the sinker, but it’s not a pitch you could build a game around.

The Dodgers made a bet that the sinker would start sinking more and Treinen would rebound. That’s not entirely what happened: He threw the sinker more often, but it sunk less and missed even fewer bats than it did in 2019. Part of that was likely intentional, as he used the pitch more often in the strike zone, but part of the reduced whiffs are due simply to the fact that the sinker from 2018 just hasn’t quite returned. Batters made a lot more contact against it, but that’s not entirely a bad thing because the result is a lot of ground balls that tend not to do much damage.

Using his sinker more often and more often in the strike zone helped, but Treinen also made improvements to the rest of his arsenal to avoid a repeat of his disappointing 2019. He upped the use of his slider, tossed fewer four-seam fastballs, and threw his cutter in the strike zone. Over Treinen’s last 10 appearances of the season plus another 11 in the postseason, he threw the four-seamer under 8% of the time. Instead, he stuck with a three-pitch mix: his sinker 42% of the time, the slider 26% of the time, and the cutter the remaining 24%. The result was just two walks against 72 batters. He got hit around a little bit, but most of the poor results were a mix of small sample and a fluky left-on-base rate. His FIP just above three might not be super-elite, but it is still very good, and there’s little reason to think he won’t be a solid reliever going forward, usual relief pitcher volatility caveats aside.

At a $17.5 million commitment, Treinen might be getting slightly less than the market rate from past seasons given his track record, but this is pretty close to a standard contract for a good reliever. While giving multiple years to a non-elite pitcher might not be the most optimal investment for most teams, relievers are what you get for the team that has everything, and the Dodgers have just about everything save for a third baseman. They’ve already added Corey Knebel in the hopes of a rebound, and between Kenley Jansen, Knebel, Treinen, Brusdar Graterol, Joe Kelly, and any potential starters who don’t make the rotation, the team has the makings of a solid bullpen. Los Angeles also made it that much harder for anyone else to follow suit: After Liam Hendriks, the next tier of available relievers contained Treinen, Brad Hand, and Archie Bradley. There are a lot of bullpen arms on the market, but the number of relievers in Treinen’s class isn’t large, and it just shrunk by one.