In a surprise decision, Matt Williams announced on Monday that Ross Detwiler will start the season in the Nationals’ bullpen instead of in the starting rotation’s fifth spot. Adam Kilgore of the Washington Post had the news first. Detwiler, who has made major league starts in each of the last five seasons, is a former first round draft pick and was the best starting pitcher in the team’s 2012 playoff appearance. Williams named Taylor Jordan, Tanner Roark, and Chris Young as possible starters in his stead.
After this move, you’ll see and hear people citing Detwiler’s previous bullpen success as a reason for moving him there this season. Admittedly, his 1.11 ERA and 1.052 WHIP look like appealing stats as a reliever. But, what are some other factors that could have, and should have, gone into this decision?
Multiple times through the order – Detwiler has struggled when facing opponents for the second and third time through the order as a starter throughout his career. When facing the opposing batter for the second time, opponents hit .300 against him with a .787 OPS. The third time through gets even worse with opponents hitting .324 against him and an .873 OPS. The more opposing hitters get to see his stuff, the less he’s able to fool them. I truly believe this is the principle reason that the team decided to make Detwiler a reliever.
Advanced metrics – Some advanced metrics don’t like this move quite as much as the standard stats, though. Granted, Detwiler’s time as a reliever need a small sample size disclaimer, with just 32 1/3 innings, but the same goes for those touting his impressive 1.11 ERA and 1.052 WHIP there. He strikes out about an additional batter per nine innings in the bullpen, but he also walks nearly twice as many in relief. So, despite the increase in strikeouts, his strikeout-to-walk ration actually decreases a hair.
His FIP, or fielding independent pitching, as a reliever (4.03) is nearly identical to his numbers as a starter (4.08). But, as I’ve said before, past performance doesn’t necessarily indicate future performance. I’ll have more on why I think that’s the case in my final thoughts.
Competition – It’s easy to look at what Taylor Jordan and Tanner Roark were able to do last season and get the impression that they are why this move was made. It wasn’t. Detwiler’s bullpen relegation is all about what he can do, not about who may replace him.
Final thoughts – The only time we’ve seen Ross Detwiler as a reliever is when he was waiting to be in the rotation, like when the Nats were in their last days of the Chien-Ming Wang experiment. He’s never had an opportunity to be told, “You’re going to be a reliever, so prepare for that.” That’s exactly what Matt Williams has done by giving Detwiler this news with more than two weeks remaining in Spring Training. He’s clearly hoping that Detwiler’s lethal fastball/changeup combination will work better for him when he focuses on an inning or two of work rather than six or seven innings.
He should be able to get another mile per hour or two out of his fastball, and he’ll be dealing with facing batters just once in a game, at least most of the time. Ultimately, it came down to where the Nationals saw the most value in Detwiler, and to some extent, I understand. He could have been a good starter, but he has the stuff to be great in the bullpen.