Washington Nationals rookie right-hander Tanner Roark is off to a successful start in his big league debut: he is 7-1, 1.74 ERA with a 37/10 K/BB ratio in 46.2 innings. He was also on nobody's prospect list pre-season, so how did this guy arrive in Davey Johnson's Gulch? Who is Tanner Roark?
Roark pitched college baseball at the University of Illinois. By 2008 he was pitching for Southern Illinois in the independent Frontier League, but he caught the eye of the Rangers and was selected in the 28th round of the MLB draft that spring. He had a good year in the California League in 2009 (10-0, 2.70 ERA, 91/27 K/BB in 87 innings). He continued winning games in the Double-A Texas League in 2010 (10-5) but with less impressive peripherals (4.20 ERA, 75/33 K/BB, 113 hits in 105 innings).
He was traded to the Nationals for Christian Guzman that summer. In 2011 he posted a 4.69 ERA with a 92/39 K/BB in 117 innings for Double-A Harrisburg, then put up similar lines at Triple-A Syracuse in 2012 (4.39 ERA in 148 innings, 161 hits allowed, but a 130/47 K/BB). This year he had a 3.15 ERA with an 84/20 K/BB in 106 innings in Triple-A before his promotion. He's done the best pitching of his career this year.
Roark is a 6-2, 220 pound right-hander, born October 5, 1986. This is a report I wrote on him early in 2011, based on seeing him in action in 2010.
His fastball isn’t especially fast at 86-88 MPH, though did see him hit 91 a few times in a start for Frisco. He mixes in a curveball and changeup, both solid, and he throws strikes. He adapted well to Double-A last year, the hardest test for a finesse pitcher, and he’s shown the flexibility and adaptability to pitch in any role. Roark may be just a Quadruple-A guy, but he’s earned a shot at higher levels and could end up seeing major league action in ’11 if the quarks dance properly.
Well it turned out that the quarks didn't dance properly until 2013, but here he is.
Roark's velocity has picked up over the last two years: he's worked at 89-94 for the Nationals and topped out at 95, compared to the 86-88/91 max readings from his days in the Rangers system. He still has the curveball and change, but uses a slider more often than he did a couple of years ago. He keeps the ball down and throws strikes, as he always has. Roark himself credits a more aggressive mental approach for helping him develop. The extra velocity must have something to do with it as well.
Overall, I don't see any reason to think that Roark is going to be an outstanding pitcher in the long haul, but as long as his command holds up I don't see any reason to assume he is going to fall on his face, either. You could do a lot worse for a fourth starter/long reliever, and even bullpen work is a good fate for a guy who was pitching in the Frontier League.