
1. Kelvin Herrera, CP, Kansas City Royals
Similarly, Royals righty Kelvin Herrera has been a closer this year, but he is capable of pitching in other roles as well. In fact, Herrera is at his best as a setup man. Herrera has 12 saves and a 3.68 ERA and 4.37 FIP in 22 appearances this year, with a 2.69 career ERA and 3.08 career FIP in seven seasons, with just 29 career saves (24 since he took over as closer last season).
An All-Star in 2015 and 2016, Herrera still averages 97.5 miles per hour on his fastball according to PITCHf/x. Interestingly, his current average velocity is a half-mile per hour higher than his career average despite the fact Herrera no longer hits 100 on the gun like he did earlier in his career. In fact, Herrera’s current 97.5 average velocity is higher than any he has produced in a single season.
Herrera has relied on a curveball and changeup as his secondary pitches throughout his career, but added a slider to the mix in 2016. He currently averages 89.8 miles per hour on the change, which is again the highest of his career. However, that’s not necessarily a good thing since the difference in velocity between his fastball and changeup is shrinking. He has a 13.0 career pitch value, according to FanGraphs, with his change, but the pitch has taken a step back this year to -1.4.
On the other hand, Herrera’s curveball is also faster than ever, jumping from 81 miles per hour in 2016 to 87.4 this season, and it’s proving to be a good thing. Herrera has a -4.7 career pitch value on his curve, but has posted a 0.2 this year.
Next: Top MLB prospects for 2017
With experience as a closer, and All-Star success as a setup man, as well as an evolving pitch selection and a still blazing fastball, Herrera would be a valuable addition to the Arizona pitching staff. However, he won’t come as cheaply as Norris, both in terms of prospects and money, since Herrera has one more year of arbitration and will be a free agent after 2018.