Patrick Corbin was supposed to be a back-end starter. On a team that featured Randall Delgado and Tyler Skaggs in the minors, Corbin was thought to be a temporary solution in the rotation. Someone who wouldn’t embarrass himself until better prospects were ready. But a month into the season, he’s been the Arizona Diamondbacks best starter. Corbin’s 2.97 FIP ranks him 10 among National League starters. He’s already made a case to stick in the team’s rotation once the youngsters are ready. While some regression seems inevitable, Corbin is well on his way to a breakout season.
During his rookie season, Corbin’s performance matched his scouting report. He ended the season with a serviceable 4.54 ERA and a 4.00 FIP in 107 innings. As a starter, he was good enough to stick in a rotation, but lacked upside. His stuff played up much better in a relief role, which is exactly what some analysts had expected given Corbin’s ability. As a reliever, Corbin was helped by increased fastball velocity. After sitting at 90.40 mph with the pitch in May, Corbin’s fastball averaged 92.24 mph as a reliever in July. This season, he’s throwing even harder.
Corbin is averaging 92.53 mph with his fastball while pitching out of the rotation. That’s quite the jump. With the extra velocity, Corbin’s pitches have been far more effective. Corbin’s sinker has already produced a 7.1 pitch type value, which rates as the best in baseball. The main value of the pitch has been its ability to produce ground balls. Corbin’s sinker is being pounded into the ground 55.26% of the time, according to BrooksBaseball.net. The success of his sinker has likely helped Corbin limit the long ball in 2013. Home runs were a significant issue last season, as Corbin allowed 14 in just 107 innings.
The velocity gain has also turned Corbin’s slider into a stronger strikeout pitch. Corbin’s slider has produced a whiff 26.35% of the time this season, up from 23.60% in 2012. It’s also not being put in play as much this year. Corbin realized his success with the pitch last season, and has been using it slightly more often to open 2013. It’s become his primary two strike offering against both righties and lefties. Despite the improvement, Corbin’s strikeout rate and swinging strike rates have only increased slightly this year.
One area where Corbin’s scouting report has remained accurate has been his ability to pound the zone. After putting up a 58.6 first strike percentage in 2012, Corbin has improved his rate to 71.1% this year. That currently puts him second behind Tim Hudson. His pitches have not only been more effective, but he’s putting himself in a much better scenario for success by pounding the zone early.
Increased velocity has helped Corbin outperform his projected status as a back-end starter. As long as Corbin can retain his velocity surge for the entire season, he could continue to show increased effectiveness with his pitches. He’ll also need to show that his sinker has improved enough to limit home runs at a better rate than last season. Corbin has helped himself by pounding the zone, which is the ideal strategy for a pitcher with his skill set. He won’t post a sub 3.00 ERA this year, but he’s already taken a major step forward.