The Kansas City Royals optioned Kelvin Herrera to Triple-A Omaha yesterday, and are hoping that if he spends some time working on his control and throwing all three of his pitches, he can return to his 2012 form and help this team down the stretch.
While I understand the Royals decision to send Herrera down, his general ineffectiveness has helped make their bullpen look a little shallow right now. Greg Holland has looked absolutely fantastic this season and has been one of the best relievers in baseball, but the rest of the bullpen consists of two set-up men who do not look as effective this year as they did last, and four guys you would prefer to use in long relief roles. Figuring out who to use in high-leverage roles may be a more difficult task for Ned Yost moving forward.
Lost in some of the Herrera discussion is that Aaron Crow has not pitched terribly well this season either. Crow currently sports a 4.29 ERA, and his 4.24 FIP and 4.36 xFIP suggest that he has not been the victim of bad luck. The right-hander has seen his K% drop to a below-average figure, 18.1%, while his BB% has increased to 9.6%, which is above-average. Crow has done a good job forcing groundballs, but otherwise does not look as effective as he did in 2012.
Yost has used Crow in the most high-leverage situations this season; he has the highest Average League Index (gmLI) when entering the game among all Royals relievers. Holland has the second highest gmLI while Tim Collins has the third highest. Given Crow's struggles, it might make some sense to use Collins in more high-leverage situations moving forward.
Collins sports a shiny 2.57 ERA, but there are some reasons to be concerned about his production moving forward. His K% (24.1%) is still above-average, but has dropped 24% from last season. His BB% is still well above-average at 11.2%; it will be more difficult for Collins to maintain his ERA if he is not striking out an absurd number of hitters.
The southpaw is also due to surrender more runs via the homer. Jayson Heyward's solo home run was the first round-tripper that Collins had allowed this season, and a 2.9% HR/FB% is in no way sustainable. Collins owns a 4.17 xFIP and 3.68 SIERA, which are more in line with what we can expect from the reliever moving forward.
The two relievers haven't been terrible this season, but neither have been lights out. Fangraphs credits Aaron Crow with 11 shutdowns and seven meltdowns, while Collins has nine shutdowns and six meltdowns. For comparison, Holland has 13 shutdowns and three meltdowns.
Even if Crow makes me nervous with his decrease in strikeouts and Collins worries me with his number of walks, the other options in the bullpen don't appear to be any better. None of the other relievers in the bullpen have been utilized in many high-leverage situations, nor would I feel comfortable with them in those situations moving forward.
Bruce Chen has an impressive 1.93 ERA, but still isn't striking anyone out. His 5.08 xFIP and 4.32 SIERA suggest that the former starter is more suited for the long relief role. J.C. Gutierrez is striking out less people than Chen, and was never a particularly good reliever with the Houston Astros and Arizona Diamondbacks. Will Smith is on the team, and I have no idea how he will perform (although his Triple-A numbers as a starter look pretty solid).
I may be losing my mind, but if Crow continues to struggle, the best non-Collins high-leverage option in the bullpen might be Luke Hochevar. Hochevar has a 2.67 ERA, but is also out-pitching his peripherals. His 3.08 SIERA and 3.75 xFIP suggest that he should still be an effective relief option moving forward.
The former starter has looked more impressive out of the bullpen, striking out 25% of the batters he has faced this season while only walking 6.7%. His .197 BABIP and 87.6% LOB% are not sustainable, but they aren't the only factors that have fueled his success as a reliever.
Yost has not used Hochevar in high leverage situations for most of the season, which has been the right decision so far. Given the lack of relievers that I feel comfortable with Yost using in high-leverage situations, I wouldn't argue against the Royals manager giving Hochevar a chance to pitch more meaningful innings.
It's possible that I'm a little too worried about the bullpen, given that Kansas City relievers have the third lowest ERA in MLB and that the offense has been a failwhale. The Royals bullpen, however, is 19th in FIP and xFIP, which is more in line with how I would expect them to perform moving forward. Given that the offense is not likely to give the bullpen large leads, the team needs the relief pitching to perform at a high level to keep this team in contention.
I think Collins should be used in the most high-leverage situations moving forward, but his walks are a little worrisome. Outside of Collins, you either hope Crow starts striking people out again or role the dice on Hochevar. As long as Kansas City can get the lead to Holland, the team should be fine, but getting there might be more difficult than we originally expected.