The Reds have a weird problem to have. It's a problem that most teams would kill for and it's a problem we haven't seen in Cincinnati in my lifetime. They have too many quality starting pitchers. Now they don't have an ace among them - at least not yet - but the Reds have as many as 9 pitchers that could pitch in the majority of big league rotations.
Over the last 12 games, the starting rotation has been a bright spot for the Reds. They've gone 79 innings (6.5 IP per start) and allowed just 22 earned runs (2.51 ERA). They aren't striking out a lot of hitters - just 5.1 per 9 IP - but they aren't walking many either (2.1 BB/9). In general, each of the Reds starters have been on a good streak of late:
Before you say anything, yes, I know this is selective endpointing. I'm not trying to make any decision based solely on these numbers. All I want to show is the most recent trend for these pitchers and I selectively endpointed based on where I thought the trend started.
With Edinson Volquez coming back to the rotation after the break, the Reds are going to have clear a spot out of the rotation for him. One pitcher who has hit a slow patch of late is Mike Leake. His numbers are a bit deflated by his attempt at a complete game on Friday, but he's given up 5 or more runs in 4 of his last 6 starts. Is he hitting a wall? Is the league figuring him out? That's something the Reds need to determine.
I don't expect that the Reds will take Leake out of the rotation to make room for Volquez though. My guess is that Matt Maloney will go back to the minors and Volquez will take his spot. The real question is, what do the Reds do if Aaron Harang is back and healthy after the break. As you can see, Harang hasn't exactly been chopped liver of late, but then neither has anyone else really, except Leake.
I think at this point, the Reds will have a hard time taking Travis Wood out of the rotation, at least not immediately after his performance on Saturday night. What I expect will happen is that either Harang or Leake will go to the bullpen when Harang comes back, which is to say, I expect Leake to go to the bullpen. This is not just in reaction to his recent struggles, but also because the Reds are interested in limiting his innings. It's also because in the big leagues, the veteran almost always gets their starting spot back after injury.
I don't think the Reds should settle for that easy answer though. I think they should think long and hard about moving Harang to the bullpen. There are a couple of reasons why I think that. For one, I think Harang can throw the ball harder than either Leake or Wood. His average fastball is right about 90 MPH as a starter, but according to pitch fx, he can his 93-94 still on the gun, and that's when he's conserving himself. It's not out of the realm of possibility that Harang could touch 95 or 96 if he's out on the mound for just an inning at a time.
Another reason for moving Harang to the pen is that he's basically a two-pitch pitcher already. He doesn't need any other pitches to be able to get hitters out an inning at a time, so he can mix up his fastballs and sliders and hopefully be more effective in shorter stints.
I think all three of these guys have the mound presence to be successful in the bullpen. They all have good control and I think would be able to handle the pressure of pitching late in games in tough situations. One thing I don't know is if any of them can handle getting loose quickly enough to be called on as a short reliever. This is probably one big red flag for Harang, since he's been a starting pitcher for at least a decade longer than the other two pitchers.
Another argument that gets made against Harang to the bullpen is that he often struggles in the first inning. While this is true, we shouldn't get too hung up on it because just about every pitcher does worse in the first inning. It's the only inning in the game where it is guaranteed that the 1-2-3 hitters are going to bat, and typically (unlike the Reds) teams try to put their best hitters in those spots in the order.
As they say, it's a good problem to have. I think all three of these pitchers deserve to stay in the big leagues, and I think they all can help the Reds in the second half. Given that the Reds really could use some bullpen help, I sure hope they are considering moving one of them out to the pen, at least temporarily.
NOTE: I didn't mention Homer Bailey at all because until there is any sign of him coming back this season, we don't really need to worry about him.