Today Donn Roach will make his second career start. He replaces Tsuyoshi Wada, who still has an ailing shoulder. It appears like this will be a spot start as Wada might be able to avoid a stint on the DL. The Cubs did not lose much in the all important bad name pun department with the swap, but the two pitchers’ style could not be more different.
Neither pitcher is overpowering in terms of velocity, but Wada is a flyball pitcher that relies on a deceptive high fastball to generate swinging strikes. Donn Roach, as you’ve probably heard by now, is an extreme groundball pitcher. Extreme might not do him justice. Roach had a 64.4% GB% in his 30.1 big league innings last year. Groundball data is available through 2002 at Fangraphs. Roach’s 64.4% is tied for the 58th highest groundball rate among all seasons of 30 innings or more since that time. That rate is not some sample size fluke either. Roach has maintained a 64.18% over his last 302.2 innings in the minor leagues.
There is a problem with Donn Roach though. He does not miss bats. The ERA is a sparkling 2.29 ERA in the hitter friendly environs of the Pacific Coast League, but the FIP of 4.20 points to possible luck in that mark. Roach has a .260 BABIP. This is remarkably low for a number of reasons. Defense and infields in the minor leagues tend to be worse than the big leagues so there is an expectation for BABIP to be slightly elevated at the beginning. Groundballs also tend to result in hits more frequently than fly balls. One potential skill a pitcher might have to reduce BABIP is inducing a large number of popups. Roach pop up percentage is under 4% in his last 3 years in the minor leagues but is slightly higher at 4.69%. Still not a rate that suggests it is sustainable to maintain a BABIP at that level. Roach’s 80.5% LOB% is also very high. These numbers all point to Roach’s success in Iowa being a mirage, and don’t portend well for an extended stay in the big leagues.
Donn Roach has made a remarkable transition in the Cubs system, and maybe Roach can have success with changes put into place by the Cubs very good pitching instruction infrastructure. Roach is still only 25 and pitchers can find success later in their playing careers more easily than hitters. That change is a remarkable increase in the number of balls put into play. Early in his career with the Angels and Padres, Roach managed to post strike out rates well above 15%. He has not posted a K% above 12.8% since reaching AA and beyond however. Roach also saw a dramatic increase in his walks as his strikeout rate dropped though. His combined strikeout and walk rates has not been lower than 19% in AA or higher. Roach has been the anti–Carlos Marmol and perhaps one of the most democratic pitcher in recent memory with less than 15% of his plate appearances ending in a strikeout or walk.
Another explanation for this change might be the fact that Roach is repeating AAA this year. Roach saw a dramatic jump in walks and decrease in strikeouts when he reached AA the first time in 2012. His walk rate jumped to 11.8% and his strikeout rate was an abysmal 7.4%. Repeating AA in 2013, Roach saw his walk rate drop to 6.7% and his strikeout rate climb to 12.8%. Not so coincidentally that was his best season in the upper minors according to FIP. Roach moved up to AAA and the major leagues in 2014. The strikeout remained in a similar territory in the two stops at 12.0% and 12.1% respectively. The walk rate, though, jumped up to 10.9% and 10.7% respectively. This season his strikeout rate has fallen to its lowest rate since 2012 at 10.0% but the walk rate has also dropped to its lowest in the upper minors at 4.6%. A case could certainly be made for a player struggling with his first taste of a level and then adjusting.
However, Roach is extremely fascinating to me because of his chance to be an extreme outlier. Starters that throw with that high of groundball rate and striking that few batters out are extremely rare. In fact since 2002, there have been only 23 seasons in which a starter has thrown 30 innings or more with a 60% or higher groundball rate and a K/9 lower than 5.50.
The results have been, at best, a mixed bag for the bunch. There are some solid seasons in there, but only 11 out of the 23 seasons resulted in an ERA lower than 4. Only 9 seasons of a FIP lower than 4 occurred. The odds of having success striking that few batters out is very low despite having an extreme groundball rate. But because it is rare, part of me wants Roach to have an extended audition. A few of the pitchers on the list carved out a decent career or at least had periods of success in Derek Lowe, Tim Hudson, Jake Westbrook and Chien-Ming Wang. However, a number of those pitchers most successful seasons fall out this range because their K rate ticked up above a threshold Roach has not seen since the lower minors.
Roach is a fascinating case to watch today. If he is having success today it likely will result in a lot of groundballs up the middle, but it is a tough task beating the Cardinals and their vodoo magic. I am not certain there is a long term view with Roach whose stay as the 1999th Cubs player in history might be very short. There is some precedent for a pitcher to be able to have success with this formula of extreme groundball rate and low strikeouts, but the odds aren’t in favor.