Reds have the advantage
The Reds depth of pitching gives them the advantage the rest of the way.
1. Bailey is well rested and healed up. Remember what he did last August and September? I won't be surprised if he dominates again
2. Volquez is starting to get his control back. He's got a fresh arm with no risk of getting tired since he didn't start pitching until July. He's going to be the Ace of the staff the rest of the way.
3. Arroyo never seems to wear out
4. Cueto will be helped by getting a week of rest
5. Wood looks like Cliff Lee every time he starts. I don't see him slowing down.
6. If anyone faulters or if Wood needs to be skipped to keep his innings down for the playoffs, they still have the potential of Harang coming back in September with a fresh arm. Or giving Leake or Maloney a start in September
Compare that to the Cardinals? None of their arms are fresh unlike Bailey and Volquez. They are running out of innings for Garcia. They are giving him a couple extra days now and have to use Kyle Lohse instead who just had surgery in May. Lohse has had only one decent outing in AAA rehab where he gave up a run in 7 innings. That would be like us depending on Harang as our #4 starter.
Now let's look at the bullpen. There are no apparent holes in the pen with the exception of Cordero. But he hasn't pitched now in what 6 days? That may help him. Everyone is waiting with baited breath to see when Chapman is added and where he fits. Other potential help in September of needed may include Burton, Springer, Izzy, or even Harang or Bailey (depending on which one forces their way into the starting rotation).
For a 5 game series I'd take the Cardinals staff because of their big 3. But for the last 6 week push when guys wear out, I'd take the Reds because of all this depth. Advantage: Reds