Before the 2013 season, the Kansas City Royals made drastic changes to their starting pitching. As a result, Royals starters finished the season with a 3.87 ERA, up from the 5.01 they posted last year.
In addition to this, Royals starters pitched 96 2/3 more innings than last year. This allowed an excellent Royals bullpen to have plenty of rest. This article focuses on two pitchers who combined to give the Royals innings at the back of a rotation which greatly exceeded expectations, Bruce Chen and Luis Mendoza
After a successful 2011 campaign, the Royals signed Chen to a 2 year/$9M contract. According to FanGraphs, Chen was worth $16.1M to the Royals over those two years.
Chen certainly earned his keep in 2013, posting a 3.27 ERA in 121 innings. After transitioning to the rotation on July 12th, Chen posted a 3.61 ERA while averaging almost 6 IP per start.
Chen had a brilliant stretch of three starts from August 3-13th, pitching 20 2/3 innings, striking out 16, walking 4, and lowering his season ERA to 1.62 while the Royals were in the middle of a postseason race.
Unfortunately, Chen posted a 5.73 ERA in his next nine starts, his luck perhaps catching up to him. Chen was undeniably very lucky last year. While he has possessed the ability to limit hits during his career, Chen held batters to a career low* .255 BABIP last year.
In addition to this, Chen also had the lowest home run to fly ball ratio of his career, his 6.7% HR/FB being almost half his 11.9% from last year and his 11.5% career rate. This helped Chen immensely because he’s an extreme fly ball pitcher. Overall, he was a cost effective option at the back end of the Royals rotation who performed very well in his role.
*:As a rookie with the Braves, batters had a .209 BABIP against Chen in 51 innings, but the low number of IP eliminated this season from consideration
Hoping to follow up on a successful 2012 season, Mendoza started off 2013 with a bang, pitching very well in his first start against the Phillies. Unfortunately for Mendoza and the Royals, it was all downhill from there.
Mendoza started 14 more games for the Royals, posting a 5.3 ERA in 73 innings. After giving way to Chen in the rotation, Mendoza only pitched 12 2/3 more innings for the Royals, giving up 12 ER.
Mendoza has now signed a deal to play baseball in Japan, presumably in an attempt to build his value for a return to MLB.
Without the ability to strike out enough batters to be successful, Mendoza relies heavily on ground balls to keep his ERA down. With the Royals excellent defense and a 50% GB rate, Mendoza should have been able to live with an ERA in the mid 4′s for the Royals.
Instead, his walk rate swelled to the largest of his career and he, along with his glorious mane of hair, was sent packing.