Odd Man Out: Cardinals' potential playoff rotation

Four year ago today, the Cardinals were ten games behind in the division and 10.5 out of the Wild Card Race. The Cardinals franchise has not been alone in first place on today's date since 2009, Matt Holliday's first full year with the club. These are small reminders that standings can fluctuate, even in the last month of the season. These reminders are necessary only as a caveat for the remainder of this piece as it discusses a potential playoff rotation six weeks before the start of the playoffs.

The Cardinals sit in very good position to qualify for the playoffs with a 13 game-lead for the wild card, although that would be a major letdown given the Cardinals' position in the standings all season. Still, a 3.5 game lead on the Pirates and 6.5 game lead on the Cubs gives the Cardinals solid footing with 38 games left in the regular season. FanGraphs gives the Cardinals a 68% chance to win the division. Baseball Prospectus puts the Cardinals at 75% to win the division. There is still a lot of season left to go, and a lot could change in the standings and in the performance of the Cardinals' starters, but if the playoffs started today, or in the alternative, if things stay as they are, my playoff rotation would be Lance Lynn, Michael Wacha, Carlos Martinez, and Jaime Garcia.

Cardinals' pitching has been the focus all season long, and for good reason, the team has put together an incredible run, and all five starters have pitched well, from FanGraphs:

All five starters would be good fits in a playoff rotation, but one of them is likely to be left out of the Cardinals' rotation. John Lackey has the highest ERA, FIP, and xFIP of the group making him at first glance, the pitcher who has performed a bit behind the rest of the rotation. However, innings matter, and innings have especially mattered to a Cardinals team that was in real danger of having an innings shortage after Adam Wainwright's injury. Lackey leads the team in starts and has averaged roughly 20 outs per start, just behind Jaime Garcia in terms of starts per innings. Lackey has pitched very well for the Cardinals all season long and has likely earned himself a qualifying offer and a potential multi-year deal on the free agent market. That does not make him one of the best four options for a postseason slot at this point.

Looking solely at ERA, FIP and xFIP, we can create a few different tiers. Carlos Martinez and Jaime Garcia are in the top tier. Of the five, they are the only pitchers with outstanding numbers in all three categories. In the next tier, we have Lance Lynn and Michael Wacha, who both have a very goof ERA and FIP, but are lacking slightly in xFIP. In the third tier, we have Lackey, who sports the excellent ERA along with a solid FIP and xFIP. These tiers are not definitive, but adding in FIP and xFIP to compare with ERA is helpful. Both FIP and xFIP are better predictors of ERA than ERA itself is, which means that the players are more likely to have an ERA the rest of the season that matches up with their FIP, providing an advantage to the rest of the rotation over Lackey. The projection systems bear this out as Lackey's ERA is projected to be good, but higher than the rest of the rotation going forward.

The Cardinals might very well continue to outperform their FIP due to the park they play in and the quality of the defense, but to the extent that is true for one pitcher, it should be true for all. Looking closer at the FIP and xFIP differences provides a bit more information on the starters. We see El Gallo and Garcia with xFIP's very close to their FIP while Wacha and Lynn are higher. The xFIP (which uses an average home run rate instead of actual home runs like FIP) is explainable by park and the type of pitcher. Looking at ground ball percentage above, we see that Martinez and Garcia are ground ball pitchers. Martinez's 55% rate ranks sixth among qualified pitcher, and Garcia's 67% rate is first among pitchers with at least 80 innings. Their home run rate does not need to be normalized for xFIP because it is already close to normal. They prevent home runs by keeping the ball on the ground. Both Garcia and Martinez have been excellent on the road when they have not had the benefit of their large home park.

Wacha and Lynn are flyball pitchers. They benefit from a spacious Busch Stadium that keeps many potential home runs inside the stadium. Both have home ERAs that are much better than on the road. As a result, I would start Lynn and Wacha in games 1 and 2 of the playoffs if the Cardinals have home field advantage. This is where things get tough for Lackey. He also has some of the same flyball tendencies as Lynn and Wacha, but he is simply a cut below their level. He does not strike out as many hitters and even with the low walk rate, he is vulnerable on the road. He cannot beat out Lynn and Wacha in Game 1 and 2, and when the Cardinals go on the road, he is not as ideally suited to succeed as Martinez and Garcia.

Lackey is a veteran, but all of the Cardinals' pitchers have playoff experience, and they have pitched better than Lackey this season. The Cardinals appear to have abandoned any pretense of innings limits with Wacha and Martinez, and while that is a somewhat risky decision, it would be foolish to limit them in the playoffs once the Cardinals get there. The potential is just too great to pass up when chasing a championship. Lackey is a valuable player, but if the team is going to hand the ball to one pitcher to try and shut down opponents, Lynn, Wacha, Martinez, and Garcia make the most fearsome foursome the Cardinals have available to them.