Deleting the Adjectives: The Drew Storen Enigma
When the Nationals signed Rafael Soriano this offseason it supposedly set up a nigh unbeatable triumvirate in the bullpen of Soriano, Drew Storen and Tyler Clippard. All were elite relievers who had experience closing out games, combined they would shut down opponents in the later innings.
But that hasn't been the case this season. All three have had their struggles, but none as much as Storen. Just a year away from a 43 save season Storen currently has a 4.85 ERA, 4.14 FIP and 1.54 WHIP. While not in the closer role this season Storen already has three blown saves, just two less than in 2011 when he was the full-time closer. Storen isn't that bad, his talent was not suddenly stolen away from him by the aliens of Moron Mountain, so why is he having so much trouble this year?
Some postulated earlier in the season that he was still shell shocked from his blown save in Game 5 of the NLDS. While that was certainly a heartbreaking moment that likely took a while to get over, it is highly unlikely that a professional would let it affect him eight months later.
Looking at his peripheral stats there is nothing that stands out as an issue. His 8.31 K/9 and 2.42 BB/9 are right around his career averages. He is giving up a few more home runs, his HR/9 is 1.38, but that alone isn't enough to explain how he is struggling this much.
What does stand out is that opponents have a .358 batting average on balls in play against Storen this year, significantly higher than his career average of .282. This inflated BABIP suggests that Storen could be a victim of bad luck and when we peel back further we can see more evidence of this.
Looking at his batted ball data on Fangraphs, Storen is giving up the same type of contact as he was before. His 1.62 ground ball to fly ball ratio is right around his career average of 1.33 and isn't close to being a problem. Where Storen is having trouble though is infield hits, 9.5% of ground balls he has allowed have been an infield hit. For comparison's sake, Ichiro Suzuki, who was one of the best at beating out infield hits, has a career IFH% of 12.5%. So an inordinate amount of batters are getting on-base even when Storen induces weak contact.
But chalking it up to bad luck and calling it a day is too simple. There's one more difference between this year and previous seasons for Storen. Both PITCHf/x and Baseball Info Solutions agree that he is using his fastball significantly less than in previous years with his change-up use rising accordingly. In 2011 and 2012 Storen threw his fastball around 64.9% and 71.4% of the time, but he's only throwing it 56.1% of the time this season. With his slider rate staying mostly the same he has been using his change-up more, 15.7% of the time versus a career average of 3.5%.
It's certainly possible that Storen is trying a new approach in attacking hitters that is leading to the increase in infield hits and home runs. However, with his K/9, BB/9 and GB/FB ratio not being substantially different as well it seems unlikely. SIERA, an ERA estimator that is a good measure of a pitcher's underlying talent level agrees, pegging Storen at a great 3.20. Look for the BABIP, IFH% and HR/9 rates to regress to Storen's career averages as the season goes along and his big picture numbers to back to what's expected of the talented reliever Storen still is.
Want to read another good Nats blogger, who is almost as smart as me, come to the same conclusion by different means? Then read this by Luigi de Guzman at Natstradamus.