So, Who’s Heading to The Bullpen?

It’s easy to look at a complex situation and see it as a problem. We do this all the time — some might even call it a habit. When the answer to a question is jumbled and convoluted, we tend to see it through a lens of negativity. The Diamondbacks have too many starting pitchers at the moment. But that’s not a problem, it’s an opportunity. There’s a chance to get something of value from the surplus, and dealing from a position of depth and strength is always preferred compared to the alternative. Thus far, the D-backs have been unwilling to accept a trade for one of their surplus starters, and while that’s still not out of the question (some contender will have a pitcher go down in February or March), it seems more likely that one of the “extra” starters winds up in the bullpen. With Zack Greinke, Robbie Ray and Taijuan Walker essentially guaranteed a rotation spot, it’s worth wondering which of Patrick Corbin, Archie Bradley, or Shelby Miller would make the best reliever?

Now, this isn’t as easy of a decision as it may look on the surface. You can’t just relegate Shelby Miller to the bullpen because he was atrocious as a starter last season. Just because Patrick Corbin pitched well in that role last season doesn’t mean that’s his optimal role this season. And the fact that Archie Bradley is still young doesn’t necessarily mean he’ll ever mature to become the excellent starting pitcher that was once forecast. There’s no snap judgement that will give us a clear answer here. Instead, we need some kind of framework from which to evaluate this decision. Setting those parameters, however complete or incomplete they may be, is the first step. Some things to consider include:

• Stuff that can play up in shorter stints: starters pitching out of the bullpen often see their velocity tick up by 1-2 miles per hour in shorter bursts since they’re usually pitching for just an inning or two, not five to seven. This may help sharpen breaking pitches, too.
• At least one plus offering: starting pitchers generally need three average or better pitches to succeed in the rotation. Relievers, however, can often get by with just two pitches, especially if one of them grades out as plus and the second pitch can play to at least average.
• Swinging strikes: those plus pitches mentioned above are important because these are the kinds of pitches that are often swung at and missed. It would be beneficial for the candidates to have at least one pitch that can miss bats with regularity.
• Strikeout rate: because relievers are often deployed in tight situations or inherit runners on base, strikeouts are extra beneficial. Coming in with one out and runners on the corners, getting the strikeout is paramount to surviving the inning without surrendering another run.

You may have noticed a trend above revolving mostly around raw stuff and that raw stuff’s ability to generate strikes and strikeouts. Because relievers aren’t holding back to make a second or third pass through the order, the idea is that they dispatch the three or four batters they face with as much authority as possible. Of course there are the Brad Zieglers of the world who can effectively control batted balls, but most can’t do so with enough consistency for it to become a true asset. Strikeouts, however, always play and play especially well when the game is on the line since they don’t advance runners or even provide the defense with an opportunity to bungle things.

Running a quick diagnostic on the three pitchers we’re considering here, let’s see how they stack up. Patrick Corbin has an easy plus pitch in his slider, two fastballs that have oscillated between mildly above and mildly below average, and a changeup that’s been very bad. He led the trio last year in swinging strike rate, ground ball rate, chase rate and had the mildest left/right splits. Archie Bradley has a plus offering in his curveball and has a fastball that can play up with good velocity and movement when he wants it (he also has a changeup that’s been inconsistent). His command, however, leads to all of his pitches playing down. He leads Shelby Miller in swinging strike rate, ground ball rate and contact rate, but trails Corbin in these areas. For his part, Miller didn’t show anything that looked like a plus offering last season, but that’s not really fair to him. For his career, he’s shown an effective four-seam fastball that can miss bats up in the zone and a curveball that often functional enough to get hitters out. Miller has consistently yielded the most contact of the group and has routinely provided the fewest number of ground balls.

It’s quite possible that Shelby Miller’s best value next season is his ability to log some bulk of innings while working to get himself back on track. Putting him in the bullpen could work because he’d have to worry less about the results, but it could hurt him in that it doesn’t allow much time for side work and it adds another wrinkle to a murky situation. Through this filter, it might look as if Corbin and Bradley have the best chance to be a good reliever, with Miller lagging behind. But you’ve probably caught on to something along the way. The things that would make Corbin and Bradley potentially good relievers in 2017 are also the things that could make them potentially good starters in 2017. It’s not like missing bats is bad if you’re a starting pitcher. And it’s not as if good stuff doesn’t play in the rotation. Good pitchers are good pitchers, mostly.

So how do we make this decision? How do you decide whom of Corbin or Bradley to send to the bullpen? Corbin has succeeded as a starting pitcher in the past and succeeded as a reliever very recently. Bradley’s only pitched as a starter, though without much in the way of convincing results to show for it. Both have plus breaking balls that can illicit plenty of strikes and fastballs that have shown enough in the way of effectiveness to get the job done at times, though both had trouble with the heat last season. Where Corbin perhaps stands out most is in his ability to command the baseball and produce a few more ground balls. Bradley’s raw stuff might be a little nastier, especially if he can ever get a handle on his fastball. Even though Corbin had bullpen success to close out 2016, I’d still lean towards moving Archie Bradley to the bullpen for 2017 (as we laid out in our Offseason Plan).

Let’s be clear: this will be a Spring Training decision that should come down to the wire. Maybe a starter gets hurt this spring and it never becomes a question at all. Maybe another team finally ups their offer for Corbin or Miller or someone else and the D-backs move one of their rotation candidates. Those are both possibilities. But as it stands now, the team has too many starters and that’s not necessarily a bad thing because it does provide an opportunity to find value and production. At the end of the day, I think Patrick Corbin is a better pitcher right now than Archie Bradley and I’d prefer my better pitchers in the rotation. Bradley could take off in the bullpen where he can find more fastball velocity, his hammer curve can continue to miss bats, and his command issues may not be as big of a problem. The move may be permanent, or it may be temporary. As Ryan showed us last week, there are plenty of reasons to think Patrick Corbin can be a good starting pitcher again. I’ll take his word for it, and when mixed with our understanding of what makes a strong reliever and who Archie Bradley is right now, the decision is close to but clear to me. If you’ve got to move Patrick Corbin, Archie Bradley or Shelby Miller to the bullpen, make it Bradley.