Do the Arizona Diamondbacks have too many long relievers?

Nobody in the National League had more long relief outings last year than the Diamondbacks, and it wasn't even close. Arizona saw 133 relief appearances recording four or more outs. The second-placed Phillies were nineteen back, and closer to the Rockies in sixth, than the Diamondbacks. Leading the way for us, were our trio of converted starters, who all finished the year in the top 10 for long relief outings. Andrew Chafin was fourth with 23, Randall Delgado finished equal fifth on 20, and Josh Collmenter - who didn't even join the bullpen until the second half of June! - still tied for eighth spot with 18.

There''s no denying, they were all very good in the role. Together, they were effectively as good as an ace, the triple-headed beast of Collgafin throwing a total of 197 relief innings with a combined ERA of 2.56. For comparison, among qualifying starters only Randy Johnson has had a lower ERA than that for us, and it would have ranked fifth in the league this year, trailing only Kershaw, Arrieta, Greinke and deGrom. It's particularly impressive, considering that as actual starters. over 126 games, Collgafin is 37-47 - all of the trio have losing records - with an ERA of 4.14. This is nearer Omar Daal or Doug Davis in team history. than the Big Unit.

This relief work was very necessary: no team got more innings out of their bullpen than Arizona, whose 579.1 innings was the most in the league. Indeed, since 2007, the only relief corps in the majors to have worked more frames were the 2012 Rockies. This was, in part, because the Diamondbacks got fewer innings from their starters than any other team in baseball bar Colorado. League average was 935 innings; the Diamondbacks managed only 887.1, so having relievers capable of extended outings was less a luxury than necessity. However, will it be the same situation in 2016?

We have three good reasons to think otherwise. Firstly, we have new starters in Zack Greinke and Shelby Miller. Greinke hasn't exactly been a complete-game machine of late; in three years with the Dodgers he has only two to his credit. But his shortest outing in 2015 was six innings, and two-thirds of the time (21 of 32 starts), he went seven or more. Miller was also extremely reliable: while he had some short outings, 23 of 33 were six or more, with a dozen lasting 7+. Then there's Patrick Corbin, on a strict pitch-count last year; the training wheels should largely be off in 2016, though he may still be limited on total innings.

To try and quantify what we might get, let's compare the five pitchers who made most starts for the Diamondbacks in 2015, and the most-likely five for 2016, along with their innings per start. All figures are based on last year, except for Corbin, whose figure comes from his last "unrestricted" season, 2013. There's also the average innings per start, which is just the straight arithmetic mean of the five, presuming each pitcher started an equal amount of games.

Both means are likely a little high, because we won't go through this season with five starters, any more than we did last year, and spot starts, fill-ins, etc. tend to depress the numbers. The actual average in 2015 was 5.48 innings per start, but it's really the difference from 2015-2016 which is significant. It works out at a projected two extra outs per game, 108 additional innings out of the rotation over the course of the season. Or, if you prefer, 108 fewer innings needed from the bullpen. It's why we should perhaps be asking the question in the headline. For do we really require three long relievers if our starters are, on average, working into the seventh inning each night?

If not, then this naturally follows. Who should stay and who should go? They are all very affordable. Chafin will be at or near league minimum, with five seasons of control remaining, Collmenter a reasonable $1.82 million, with a $2 million mutual option for 2017, and Delgado is at $1.27 million, and this is his first season of arbitration, so is under team control through the end of 2018.  [I keep forgetting how young Delgado is; he seems to have been around forever, yet only turned 26 on Tuesday] Chafin, with most control and the lowest price, would probably bring the highest return; yet, with the team in win-now mode, we should probably look at keeping the best for our own use.

My instinct would be to hold on to Chafin, as a left-hander, and Collmenter, who has shown more consistency and whose rubber arm would seem to be particularly useful in long relief, requiring less recovery time before going again. Delgado can be traded, for a piece that might be more direct use to the Diamondbacks this season. Not quite sure what that might be: perhaps a younger power arm for the bullpen? A backup catcher, unless anybody has heard from Tuffy recently?

Trading one of them would also free up a slot for someone else, helping address the current glut of relief candidates at the back end of our pen. If it subsequently turns out we do need more long relief, there's always the possibility of another conversion job, such as the fairly common suggestion of moving Rubby De La Rosa to the bullpen. It may not be necessary even to deal Delgado immediately, but if the team finds itself in need during the season, we can revisit this and see if we are indeed overstocked in long relief.