The Diamondbacks biggest question going into 2017 is how the starting rotation will bounce back. The team was looking towards big things with a starting five of Zack Greinke, Shelby Miller, Patrick Corbin, Robbie Ray, and Rubby De La Rosa. Of this group, four of those five starters are penciled in for the 2017 rotation and the 5th spot going to Taijuan Walker. All six of the aforementioned pitchers struggled in 2016 while also making big strides that give reason for optimism in 2017.
Zack Greinke: Greinke’s biggest issues in 2017 were injuries that limited him to 158 1⁄3 IP over 26 starts. Although his results could have been better as he posted league average park-adjusted ERA- (100) and FIP- (99) in those innings. He posted 2.2 fWAR/2.3 bWAR in 2016, which prorated to 200 IP would have been 3 WAR, which isn’t enough to justify the contract. The Diamondbacks certainly didn’t pay for an average pitcher. After a slow start acclimating to his new environment, Greinke was able to pitch like the Ace they paid for in June before an oblique injury shelved him for six weeks. That month, Greinke pitched to a 1.63 ERA, a 31/7 K/BB ratio and a WHIP of 0.91. Greinke had won 7 straight decision and the team 8 starts in a row before the oblique injury happened, which was a killer blow to the team. In 2017, he will have a superior framer and game caller behind the plate in Jeff Mathis over Welington Castillo. Mathis’ ability to steal strikes should put Greinke in more favorable counts. For Greinke, the team is expecting at least 4 WAR but really hoping for 5-6 if they have any hopes for serious contention.
Robbie Ray: Depending on what type of WAR you use, Ray is either really good (BP WAR), a rising star (fWAR), or mediocre (bWAR) in 2016. Ray’s fastball velocity spiked in 2016, a leading reason behind his elite strikeout rate. Ray’s slider isn’t special, but it gets the job done in terms of generating weaker contact and whiffs. Ray lacks a reliable 3rd pitch, which is why he gets hit hard (36.6%) and the high BABIP. Ray is at his best when he’s bullying hitters up in the zone with that mid 90s fastball and using his slider to the glove side of the plate. The one area he can improve is getting right-handed hitters out and finding a reliable pitch he can use on the outside third of the plate. Ray is very good at attacking the glove side of the plate that he can set up that pitch if he can find one. I’d like to see him work on either a sinker, change-up, or splitter in Spring, but if it doesn’t work you stick with what worked in 2016.
Taijuan Walker: Walker has been a league average pitcher the last two seasons, which is a bit underwhelming when considering his prospect pedigree. However, he pitched most of 2016 with bone spurs in his right ankle, which is never good for any RHP. Walker brings up concerns in certain situation such as getting RHB out and pitching from the stretch. Walker has been working on a slider to replace the cutter to complement his mid 90s fastball and a serviceable splitter. If Walker can continue to improve his breaking pitches as a weapon against right-handed hitters along with good health, he should surprise some fans.
Patrick Corbin: Due to salary (~$4.2M) and 2016 being a significant outlier for Corbin, I will include him in the starting rotation projection now over Archie Bradley. Ryan Morrison wrote how Corbin should be better in 2017, the one common theme seems to point at his fastball. The team forced Corbin to become more of a ground ball pitcher than let him pitch to his strengths. In 2013, he was more successful at challenging hitters in the high and inside parts of the strike zone with his 4-seam fastball. It makes sense against RHB because that sets the eye level for his back-foot slider and his token sinker, which operates to his arm side of the plate. Against lefties, Morrison asks for the approach to change against lefties, starting with more use of his more of his horizontal-moving sinker. Corbin used more 4-seamers. Most of you probably don’t have the curiosity to read the entire piece from top to bottom.
Corbin should also junk his change-up and stop throwing it more than 2-3% in any given game. It’s a pitch he has zero feel for and part of the reason why he struggled in 2016 since the last regime forced him to use it against his best interests. Morrison’s article can be summed up as “Vertical approach vs. RHB, horizontal vs. LHB”. Corbin’s best pitch is his big slider and an above average fastball. Corbin should use his 4SFB, sinker, and slider in ways to complement each other instead of pitching to a cookie-cutter approach. If Corbin cannot rediscover his 2013 or even 2015 form, then you can move him to the bullpen where his fastball velocity jumps from 92-94 to 94-96.
Shelby Miller: Miller is another case of the last regime trying to turn a successful pitcher into something he’s not. I do think Miller is very much a power pitcher, but the pitch calling from 2016 relative to his All-Star 2015 campaign was worse. Miller can get away with 70% fastballs, in large part because he throws 3 distinct types (4SFB, sinker, cutter). I believe he’s at his best when his sinker and cutter are working down in the zone to complement his mid 90s 4-seamer up in the zone. Add in a curveball as the primary offspeed pitch and mix in an occasional change-up unless there is no movement on it, you have a decent repertoire. Miller threw nearly 50% 4-seam fastballs, but unless that pitch is primarily working up in the strike zone where the extra giddy up puts the ball past hitter’s bats.
The one thing working in Miller’s favor is the raw stuff did not decline overall. Now there were instances where he sacrificed velocity for control, although that did him little help. Miller was already a natural bounceback candidate, although better pitch calling and sequencing from a veteran catcher will do him a lot of favors. I would pair him up with Mathis as much as possible as well. Miller’s best asset is his overpowering fastball and the ability to throw three different types efficiently. Better fastball usage should go a long way because when his fastballs are going good, that helps his curveball and change-up as well.
Archie Bradley: Bradley isn’t mentioned at the top of the article, but by all means has a very good chance of making the rotation should either one of Miller or Corbin fail to earn it in Spring. Bradley isn’t going to the minor leagues and in 2016 had league average FIP and xFIP numbers. Bradley is another pitcher that’s failed to live up to his prospect pedigree, but his issues are very similar to Ray. Bradley is another pitcher ruined by the last regime, as they had him ditch the slider he had worked on in the 2014 Fall League. If Bradley doesn’t get a rotation spot, I’m not sure where he fits because AAA isn’t a very useful destination unless the idea is to work on a possible 3rd pitch in the repertoire. His L-R platoon splits make him an interesting bullpen candidate if he can develop more control and can’t make it as a starter.