After Aroldis Chapman, it’s easy to argue Tampa Bay’s Jake McGee was the league’s best left-handed relief pitcher last season. He recorded a 1.95 ERA (third behind Chapman and Eric O’Flaherty) and a 1.81 FIP (second behind Chapman) over 55.1 innings for the Rays. He racked up 73 strikeouts against just 11 walks (6.6 K/BB) in the always-tough AL East, and he did so with mastery of hitters from both sides of the plate. McGee held 90 lefties to a .256/.289/.376 (.289 wOBA) line and dominated 122 righties to the tune of a .097/.157/.134 (.120 wOBA) line. Remarkably, this comes just a year after right-handers torched McGee with a .487 wOBA (59 TBF).
Now, with the Rays searching for a bat and the Nationals searching for a left-handed reliever and a suitor for Mike Morse, McGee could become the subject of trade rumors. The pertinent questions: How much of McGee’s improvement was real? Can he continue be a legitimate threat against both lefties and righties?
To begin the 2011 season, McGee put together disastrous April in which he allowed 14 baserunners in seven innings and struck out just two batters. His velocity was excellent for a left-hander at an average 93.7 MPH, but the fastball was torched — hitters went 9-for-22 with a double and a homer off the pitch, and before long McGee was shipped back to Triple-A Durham.
He was back in Tampa by July with a tweaked pitching motion. His arm slot dropped nearly half a foot after his return, and with it came the blazing velocity behind his 2012 exploits. McGee averaged 96.2 MPH on his fastball in his second stint in the majors, just under his average velocity in 2012. The results weren’t all great the second time around either — he allowed four home runs in just 21 innings back, the driver behind a 4.29 ERA. However, McGee struck out 25 against nine walks, laying the foundation for what was yet to come.
McGee’s 2012 was filled with excellence, including a run of seven consecutive strikeouts detailed here by Jeff Sullivan, an excellent illustration of McGee’s powerful fastball and three-quarters delivery. McGee significantly improved his ability to pick up whiffs with the fastball in 2012. After a 10.6 percent fastball whiff rate in the second half of 2011 (still well above the league average), McGee’s 2012 fastball drew swings and misses 14.4 percent (on 772 offerings).
McGee took his increased velocity and turned it into a devastating weapon against all hitters with improved control. He threw balls 30 percent of the time with the fastball in 2012 compared to 40 percentin 2011 against right-handed hitters and induced about eight percent more swings. McGee was already drawing whiffs on over 20 percent of swings in 2011. With more advantageous counts and swings — many defensive ones at that — on his side, adding whiffs was inevitable.
Jake McGee’s fastball has turned into one of the league’s best pitches since refinement back in Durham. Even though McGee is almost certain to allow a few more free passes and miss the zone a few more times in 2013 than he did in 2012 (particularly if he isn’t throwing to Jose Molina again), the differences were stark enough to believe the fireballing lefty can be a major back-end bullpen piece in Tampa (or elsewhere) next season.