The Washington Nationals will send right-hander Tanner Roark to the mound today against the Jake Arrieta and the Chicago Cubs in Game Four of the National League Division Series. Roark’s development as a prospect was rather unusual.
Roark pitched college ball at the University of Illinois but was not particularly successful: in 2007 for example he posted a 4.55 ERA in 83 innings with an unattractive set of component ratios, 46/33 K/BB with 102 hits allowed. By 2008 he was pitching for the Southern Illinois Miners in the independent Frontier League, but Texas Rangers scouts saw something they liked and he was drafted in the 25th round that spring after making just three indy starts.
He performed well in A-ball, posting a 2.70 ERA with a 91/27 K/BB in 87 innings for Bakersfield in the California League in 2009. He didn't show up on many prospect lists however, due an 86-88 MPH fastball that scouts questioned for higher levels. The Rangers moved him up to Double-A Frisco in 2010 and he pitched adequately, with a 4.20 ERA and a 75/33 K/BB in 105 innings with 113 hits. He was traded to the Nationals late that summer for Christian Guzman.
I saw and charted one of his Frisco starts before the trade. He showed good secondary pitches but with a fastball averaging just 87 MPH. However, he did hit 91 five times in that game. I wrote this report on him for my 2011 book:
The Nationals picked up Tanner Roark from the Rangers last year for Christian Guzman. His fastball isn’t especially fast at 86-88 MPH, though I 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. "Tanner Roark" sounds like a cartoonish hero from a bloated Ayn Rand novel. Grade C.
Roark pitched for Double-A Harrisburg in 2011 (4.69 ERA, 92/39 K/BB in 117 innings, 125 hits) and for Triple-A Syracuse in 2012 (4.39 ERA, 130/47 K/BB in 148 innings, 161 hits). Entering 2013 he really looked like a Quadruple-A pitcher: he threw strikes and ate innings, but gave up a lot of hits, didn't throw especially hard, and wasn't ranked highly on anyone's prospect list. I saw him as just a Grade C arm.
Now, if you dig really deep into the reports, you will find a few mentions that his velocity began to tick up in 2012; he was working more commonly at 88-92 rather than 86-88. He was also showing a more aggressive, less passive approach, going after hitters with greater confidence. However, since the overall results didn’t change much (yet), few people were aware of it except those who follow the Nationals farm system really closely, and the Nationals themselves of course.
In 2013 his fastball went up another notch, up to 89-95, averaging 92. This velocity gain resulted in a large leap forward in Triple-A performance (3.15 ERA, 84/20 K/BB in 106 innings for Syracuse, 85 hits) and great numbers in a major league trial (1.51 ERA, 40/11 K/BB in 54 innings, 38 hits). He continued pitching well in 2014, going 15-10, 2.85 with a 138/39 K/BB in 198 innings, 3.2 fWAR.
Roark’s 2015 season was less successful (-0.2 fWAR) but he rebounded in ‘16 (16-10, 2.83, 172/73 K/BB in 210 innings, 3.2 fWAR). 2017 saw a downswing again (13-11, 4.67, 2.4 fWAR) but he’s still a positive asset overall.
Overall, Roark has a 55-39 record with a 3.41 ERA, 120 ERA+, 586/213 K/BB in 755 innings, 10.0 career fWAR over four and a half seasons.
Roark has been better in the majors than he was in the minors, thanks to improved velocity and a better mental approach. Sometimes they sneak up on us.