A popular preseason dark horse to win one of the National League Wild Card slots was the Washington Nationals. So far, they've looked the part, and a big reason for that has been their pitching. Their starters have the best ERA in all of Major League baseball at 1.82, the next closest team is the St. Louis Cardinals at 2.63. Their ERA is supported by the best FIP and xFIP in the majors as well. The trio of Stephen Strasburg, Jordan Zimmermann, and Gio Gonzalez garner the bulk of the headlines, and rightfully so, but it is actually Ross Detwiler who leads the staff in ERA at a tidy 0.56. The question becomes, what can be expected of Detwiler going forward, and is this simply a flukey three game stretch?
For starters, he's not the best pitcher on this staff. Also, he's not going to continue to post a sub-1.00 ERA. Now that I've gotten the obvious out of the way, let's take a look at what Detwiler is. First, he's a former first round draft pick. He was the sixth overall selection in the 2007 amateur draft out of Missouri State University. With his high draft selection came a lofty prospect status. He ranked as the 51st best prospect in all of baseball by Baseball America in 2008, and was the number two prospect in the Nationals organization that year according to both Baseball America, and Kevin Goldstein of Baseball Prospectus. He failed to crack the top 100 again, but was once again ranked as the Nationals second best prospect by Baseball America, and ranked third in 2009 on Goldstein's list.
In spite of his lofty prospect status, he failed to deliver eye popping numbers in his minor league career. In 365 innings pitched across 77 appearances, 76 of which were starts, he has a 3.45 BB/9, 7.74 K/9, 3.97 ERA, and 1.50 WHIP. He has been only slightly better in his brief major league career. As a big leaguer, he has appeared in 42 games, 32 of which have been starts, and has a 3.39 BB/9, 5.59 K/9, 3.78 ERA, and 1.41 WHIP. Not exactly the type of numbers that inspire confidence that his first three starts are anything more than smoke and mirrors.
I'm here to tell you those three starts might actually signal growth, however, as there is a lot to like about what he's doing. He's filling up the strike zone, issuing just four walks in 16 innings, good for a 2.25 BB/9. He's also striking out batters at a career high rate of 8.44 K/9. Using his strikeout percentage, 24.2 percent, he ranks in the top 25 amongst qualified starting pitchers at 23rd overall. As promising as those largely pitcher controllable stats are, his growth in groundball percentage stands above both. He is currently the major league leader for qualified starting pitchers with a 64.3 percent groundball rate, just above two notorious worm serial killers, Jake Westbrook and Trevor Cahill. The combination of throwing strikes, missing bats, and inducing groundballs is an intoxicating elixir. The key for Detwiler will be to continue to do so.
Looking at his PITCHf/x data that is available on his Brooks Baseball player card paints a promising picture of Detwiler continuing on his merry way. Starting last year, his four-seam fastball gained almost exactly one mile-per-hour (mph), moving up from 92.54 mph to 93.62 mph, and he has mostly carried that velocity gain over to this season as his four-seam heater is averaging 93.32 mph. He has reached back for a little something extra in two starts this year, throwing a 95 mph heater against the Marlins, and a 95.5 mph pitch against the Reds. That is premium cheddar from a southpaw. His whiff rate on the pitch has soared from a below average 7.21 percent rate for his career, to a well above average rate of 13.04 percent. His whiff/swing PitchIQ Score on his four-seam fastball is 134, with 100 being average. Suffice to say, opposing hitters are struggling with it.
In addition to his four-seam fastball, he'll throw a sinker, which is his primary fastball, and his groundball weapon. The pitch has a below average whiff/swing rate, but of the 21.78 percent balls put in play against it, a silly 13.86 percent of them are being tomahawked into the ground. His other secondary pitches are a curveball and a change-up. When Goldstein wrote about him in his 2009 Washington Nationals Top 11 Prospects he declared his curveball his best pitch. If usage is any indication, Detwiler recognizes it is his best offspeed pitch as he is throwing it 19 percent of the time compared to an 11 percent usage rate for his change-up. The curveball is racking up empty swings 16.80 percent of the time, giving it a 116 whiff/swing PithcIQ score. While he isn't using his change-up as much as his curveball, it is also proving to be an above average swing-and-miss pitch as well. Both pitches are also coaxing groundballs at a high rate when opposing batters are putting them in play.
While it is tempting to dismiss Detwiler's first three starts as a flash in the pan, he wouldn't be the first late blooming southpaw prospect (Cliff Lee immediately comes to mind). He should be rostered in all but shallow mixed league formats, and has pitched well enough to earn one-to-two rough turns before being cast back to the curb.