Why Nathan Karns was the right choice for the rotation

Headed into spring training, the Royals had a lot of questions marks. One of those questions marks was which five pitchers would break camp as starters, and Ned Yost has answered that question by naming Nathan Karns as his fifth-starter, joining Danny Duffy, Ian Kennedy, Jason Hammel, and Jason Vargas. Karns beat out former All-Star Travis Wood for the slot, who excelled out of the Cubs bullpen last year with a 2.95 ERA in 77 appearances.

The move certainly isn’t sexy, as there haven’t been a great deal of sexy fifth starter picks in the annals of history. Nonetheless, the move was the right one, and it goes against the grain with recent moves, as Yost has historically preferred power arms in the bullpen.

So why Karns over Wood? Wood struggles against right-handed hitters, as illustrated by Dave Cameron at Fangraphs. Wood was one of the worst lefties at facing right-handed hitters last year.

Wood’s pitches work very well against left-handed hitters, and the Cubs maximized the number of lefties he could face without turning him into a pure specialist. But as a starter, that simply isn’t possible, and Wood’s job would then to be roll through heavily right-handed line-ups.

Much of the reasoning for choosing Karns likely stems from Wood’s limitations.

However, don’t sell Nathan Karns short. There are reasons to believe that the Royals like his upside, part of why they were willing to part with Jarrod Dyson to acquire him from the Mariners.

One of those reasons was mentioned by Yost:

The argument could be made that Karns’ arm talent is surpassed only by Danny Duffy in the Royals rotation, and that includes Wood. He possesses a mid-90’s fastball, topping out at 97, as well as power curveball. This is evidenced by his ability to strikeout hitters. Among the eight starting pitchers who were either in the rotation last season or figured to be in the rotation in 2017, Karns has the highest strikeout percentage and the second highest K/9.

On top of his strikeout numbers, there is also an argument that his setbacks in 2016 might have been a bit exaggerated. One indicator of this is the wide difference between his ERA (5.15) and FIP (4.05). In fact, among those eight starting pitchers mentioned earlier, Karns’ FIP is the second-lowest. His .327 opponent BABIP may have had something to do with that.

Add in the fact that he induces a fairly high rate of fly balls, which has historically benefited pitchers moving to Kauffman Stadium, and you at least have a potential recipe for success.

As a franchise whose starting pitchers ranked 27th in WAR among 30 teams in 2017, it is hard not to at least feel a little bit better about this rotation than the rotations of years past. The emergence of Danny Duffy, as well as the consistency of Ian Kennedy, the addition of Jason Hammel and a healthy Jason Vargas gives this rotation more stability than it had in 2016, or even 2015. Rather than have a fifth starter that works as a liability to that stability, Karns might actually just help the cause.