Washington Nationals reliever Blake Treinen looks sharp since recall

Considering that he's probably the Nats fifth or sixth best reliever, I feel like I've written an awful lot of words about Blake Treinen this season. The 27-year-old righty has been a hot button topic for much of the year. He began the season working in high leverage spots because Casey Janssen was on the disabled list, but struggled early on. He's shifted all over the bullpen, pitching as a setup man, a middle reliever, and even occasionally serving as a long man who can throw multiple innings and save the rest of the bullpen. Treinen has certainly had his ups and downs in 2015. You need look no farther than his strikeout and walk ratios to find both improvement and decline to find a couple of them...

• He's shown tremendous improvement in the strikeout department. Treinen has a 9.41 K/9 rate in the big leagues this season as compared to 5.33 K/9 when he worked as a starter last season. He was never a big strikeout pitcher as a starter in the minors either, with 7.14 K/9 in AAA last season and 6.52 in AA in 2013.
• Unfortunately, he's countered the higher strikeout rate with a significantly higher walk rate. From 2011-2014, Treinen never had a walk rate higher than 2.50 at any level. This season, he's checking in with 4.01 BB/9 at the big league level.

Given Treinen's raw stuff, it's not surprising to see his strikeout rate finally play up. He features a massive sinking fastball that sits in the mid-90s and will occasionally touch 98. His primary secondary offering is death to right-handed hitters, as he's shown dramatic improvement with his slider in 2015. Treinen's average slider velocity has ticked up from 84.3 MPH last season to 86.6 MPH in 2015. He's also used it quite a bit more often in 2015:

*Numbers are a percentage of pitches. Data provided by Brooks Baseball

We'll note that Treinen has pretty much nixed the changeup so far this season. He's relied primarily on that sinker as his fastball, but he's been using the four-seamer quite a bit more often (predominantly against lefties) since his return. That slider usage has kicked up from less than 15% in most months in 2014 to 30% in 2015. It's generating a ton of swings and misses per their player card on Treinen, and we can see it in Fangraphs Pitch Values. Treinen's slider was good for 2.7 Runs Above Average in the majors last season. This year, it's been good for 5.8 RAA so far.

One of the big problems for a fastball/sinker and slider pitcher is that they can be prone to high platoon splits. The slider breaks in towards opposite handed hitters, making it far less effective than it is against same handed hitters. The sinker (Treinen's primary fastball) tends to break more towards the middle of the plate towards lefties. If you've ever heard the phrase "hard in, soft away" before, this is what it's describing. Fastballs bearing in on a hitter tend to be far more effective than off-speed pitches. At the same time, hitters prefer to be able to extend their arms against fastballs, and opposite-handed hitters can see the break on an off-speed pitcher better if it's moving towards them.

Of course, we've seen this with Treinen throughout the 2015 campaign. In fact, we've seen that his platoon splits were pretty huge throughout his minor league career as well. Here's a chart from a story I wrote about Treinen in late April:

Those are Treinen's career splits against left-handed hitters (including the minors). They're pretty nasty. His struggles against left-handed hitting are nothing new, so we should never have been surprised to see him have a wide disparity in his platoon splits in the majors. Matt Williams shouldn't have been surprised either, but it seems like he was. Here's another blast from the recent past......

Those are Treinen's splits this season at the time of his demotion to AAA Syracuse. The massive platoon split is quite evident if you look at each and every column above. Perhaps the most important column to look at is the TBF, though. Any pitcher who has struggled as badly as Treinen has throughout his career against left-handers shouldn't be facing roughly the same amount of right-handed and left-handed hitters. Treinen had faced 89 lefties as compared to 91 righties at the time of his demotion.

I've hammered Williams quite a few times in this column this season for not being able to adapt, but he's done a better job with Treinen since he was recalled in August. Let's have a look at Treinen's splits since being recalled on August 6:

Of course, some of us will remember that one of those three hits that he allowed was a game-winning single by lefty Ben Paulsen (scored an inherited runner) against Colorado last week. Still, we'll note that Treinen is seeing a lot more right-handed hitters (62.5%) than lefties since being recalled from Syracuse, as opposed to the 91-89 split that he saw before his demotion. It's encouraging to see Williams make better use of his resources.

This is too small a sample to say that Treinen has really figured out left-handed hitters, but it's been nice to see some improvement, so the increased usage of his four-seamer against them might be a trend that the Nats would like to see continue. It's also nice to see Treinen's control has improved a bit in that small sample so far. One of his greatest strengths as he moved through the minors was that he pounded the zone, issuing fewer than 2.5 free passes per nine innings. In 10.2 innings since returning, Treinen has walked just two batters.

At 27 years old, Blake Treinen is no longer a prospect. However, his raw stuff and his current service time make him exactly the type of bullpen piece that teams can build around. He's got an electric sinker/slider combo, which could make him a useful arm near the back of the bullpen (particularly if he can figure out a way to improve against lefties). He's under club control through 2020, and won't even hit arbitration until after the 2017 season (read: he's cheap!). Hopefully his play since returning from Syracuse is a sign of things to come during the rest of his career.

Today's musical selection is for @ouij: