Here we are in the second half of August, with the Cardinals again fighting for a playoff spot. The team currently is tied with the Marlins for the second Wild-Card, and three and a half games behind the Dodgers, who hold the first Wild-Card spot. The Cards are far from assured a playoff spot, but it's getting to be about time to contemplate how the rotation will line up with a possible Wild Card spot.
In 2016, the Cardinals have not messed with the rotation much. Some teams will use days off to skip weaker starters in favor of getting their better pitchers more starts. The Met's recently did this to get Noah Syndergaard a start a day earlier, as they optioned Logan Verrett to the minors. Perhaps because of the concerns with the rotation as a whole, the Cardinals have not done this.
Adam Wainwright is coming off a season lost from his Achilles injury, and has also racked up a lot of innings since his first Tommy John Surgery. Scouts have always had durability and stamina concerns with the smaller Carlos Martinez, whose 2015 season ended in September due to shoulder issues that the team certainly doesn't want to spark back up. Michael Wacha's rare forearm issue could easily keep him from ever being a 200 inning pitcher. It's a miracle that Jaime Garcia has been healthy the whole year considering his past. Mike Leake is the only pitcher without any obvious red flags, but he's not exactly a guy you want to take starts from someone else.
There was a situation earlier in the year when the Cardinals moved Carlos back a few days as a precaution, and now Wacha is on the D.L., but otherwise, each starter has taken the mound every fifth game. After tonight's game, started by Jaime, the Cardinals will have 43 more to play. If the Cardinals continue to follow a no-skip rotation, Michael Wacha's rotation spot, currently held by Weaver, would be up in game 162. That game takes place on October 2nd, with October 3rd used for any tiebreaker scenarios.
Then the playoffs begin on October 4th. However, in the name of ratings, only one Wild-Card game is played a day, so we don't yet know if the N.L. Wild Card game will take place on October 4th or 5th. The next spot in the rotation would be Mike Leake. I know this might scream "Doom!" to you, but Wacha has actually been the team's second-best starter by FIP, and Leake has been the second-best starter by xFIP.
Season-to-date performance is not the most predictive metric we have though. According to Steamer and Zips' Rest-of-season projections, here's how the Cardinals rotation members currently rank:
So, what to do the Cardinals do? With at least one day off before the N.L. Wild Card game, the team could skip Leake's spot and start Garcia in the winner take all game. The set-up then would be for Martinez, Wainwright, and (assuming he comes back healthy) Wacha to pitch the final series of the year, Garcia in the Wild-Card game, and then have Martinez and Wainwright pitch in the first two games of a potential NLDS series. Either Carlos or Adam would be able to take the hill for a possible game five.
The way the rotation lines up, I don't think it's necessary for the Cardinals to do anything more than that. Some might feel a need for the Cardinals to get creative, and perhaps skip Leake and or Wacha/Weaver's spot in the rotation, and end up with a better rotation in that final series against Pittsburgh.
That's not feasible though, because the timing of the Cardinals' days off don't work out well for skipping starts. The next off day, the 18th of August, would be Wainwright's turn in the rotation, and it doesn't help at all to skip a Waino start. It would allow the team to skip Weaver and have Leake start on normal rest on the 19th, but that would leave no one to pitch the 20th, unless the team wanted to start Jaime again on short rest.
The next day off after that is the 22nd, which would only allow the Cardinals to skip Jaime. If Garcia has something going on that he needs rest for, then that would be the time to skip him. Otherwise, he's been one of the team's best starters this year, and it doesn't make sense to skip him. The team could skip Leake on the next day off which comes on September 1st, but doing so would line Garcia up with the team's last day-off, so it doesn't help.
September 1st is the only day-off where it makes sense to skip a starter, and it doesn't really do the Cardinals any good. It would set up the final series to go Wainwright-Wacha-Leake, with the option to pitch Carlos or Jaime in the Wild-Card game (or, if there not playing until October 5th, Waino would also be in the mix). That's not really better than Martinez-Waino-Wacha with Jaime for the play-in game.
So with that in mind, it seems like the Cardinals' rotation is already set. Perhaps the Cardinals have been planning this all along, who knows. If they weren't, it's too late to adjust to something different. However, the situation is set up pretty well. Without a clearly superior ace, the Cardinals just needed to make sure one of their top three starters was set-up to pitch the Wild Card game, and one of them is. They also get to throw the other two in the final series of the year. That's about as good as it gets. All that's left is to hope that the Cardinals are still playing after October 2nd.