The Cardinals' pitching has been excellent on a near historic level so far in 2015. The Cardinals' excellent starting pitchers have gotten a lot of credit for the team's success, but they have at times overshadowed what the Cardinals' bullpen has done. As a unit, the Cardinals' bullpen is first in the majors in ERA (2.59), second in FIP (3.39), and third in fWAR (5.0).
Despite this high level of success, there are a fair number of questions about the bullpen heading into the final two weeks of the season. The Cardinals were concerned enough about their bullpen that they added two experienced arms (Jonathan Broxton and Steve Cishek) at the trade deadline. Even with these acquisitions, there have been some question marks about which relievers should pitch in what spots in order to bridge the gap to closer Trevor Rosenthal. Mike Matheny has used some combination of Kevin Siegrist, Steve Cishek, Jonathan Broxton, Seth Maness, and Randy Choate in relatively high leverage situations, all with varying degrees of success. With expanded rosters, there are now even more pitchers available who could theoretically be auditioning for a spot in the playoff bullpen.
With that in mind, here is a quick summary of the 2015 stats of all the Cardinals' relievers still on the active roster.
|Miguel Socolovich"]" style="padding: 2px 3px; font-size: 110%; white-space: nowrap; vertical-align: bottom;">Miguel Socolovich||26.1||21.6%||8.1%||48.1%||1.71||2.84||3.80||0.3|
|Carlos Villanueva"]" style="padding: 2px 3px; font-size: 110%; white-space: nowrap; vertical-align: bottom;">Carlos Villanueva||57.1||22.0%||8.1%||42.2%||2.98||3.79||4.03||0.2|
|Matt Belisle"]" style="padding: 2px 3px; font-size: 110%; white-space: nowrap; vertical-align: bottom;">Matt Belisle||31.0||17.5%||10.2%||50.5%||2.90||3.47||4.33||0.2|
|Tyler Lyons"]" style="padding: 2px 3px; font-size: 110%; white-space: nowrap; vertical-align: bottom;">Tyler Lyons||44.2||21.5%||7.0%||40.9%||4.03||4.78||3.65||0.0|
|Sam Tuivailala"]" style="padding: 2px 3px; font-size: 110%; white-space: nowrap; vertical-align: bottom;">Sam Tuivailala||12.1||27.8%||13.0%||50.0%||2.92||4.53||3.61||0.0|
|Mitch Harris"]" style="padding: 2px 3px; font-size: 110%; white-space: nowrap; vertical-align: bottom;">Mitch Harris||26.0||11.0%||11.0%||44.9%||3.81||5.65||5.74||-0.3|
The Cardinals currently have a whopping twelve relief pitchers at the moment, and this does not include the one starting pitcher who will inevitably move to the bullpen once the playoffs start. (For the record, I think this starter should be Lance Lynn, and yesterday's disastrous start made that decision all the more likely.) As things stand right now, the Cardinals' playoff bullpen will almost certainly include Trevor Rosenthal, Kevin Siegrist, Seth Maness, Jonathan Broxton, and Steve Cishek. Rosenthal and Siegrist have been absolutely dominant this season and figure to receive the most high-leverage assignments. Maness, Broxton and Cishek have not been quite as good, but they have not been terrible either, and they all have solid track records of success.
That leaves two spots, and I would imagine that one of those spots belongs to Randy Choate, although I don't think his spot is as guaranteed as the other relievers previously mentioned. His job is to retire left-handed batters, many times just one per game, but in 2015, Choate has been more hittable than usual. Left-handed batters have hit .265/.333/.370 (.313 wOBA) against him this year in 91 plate appearances this season. Due to the small sample size, I am not too concerned about these numbers, given Choate's extensive trackrecord. However, Choate's usefulness is already limited by the fact that he should never face right-handed batters. If the Cardinals believe that his effectiveness against left-handed batters has declined in any way this season, then they may find it difficult to justify giving him one of their few available bullpen spots, especially given Mike Matheny's previous comments regarding Choate's usage. Ultimately, Choate will probably make the roster by default, since it is hard to see anyone else filling the LOOGY role in 2015.
After those six pitchers, it is hard to know who has a leg up on the seventh and final bullpen spot for the playoff roster (not counting the starting pitcher who gets bumped to the bullpen). Carlos Villanueva has had this spot for the entire season and been a serviceable long reliever for the Cardinals. His peripherals are not outstanding, though, and he would probably go unused as a long reliever in the playoffs, especially with a starting pitcher already available to fill that role. If Matt Belisle shows that he is healthy, I would imagine that he would be a strong candidate for this final bullpen spot. He has been used in more short-inning situations, and his veteran status and major-league contract would make him a very uncontroversial choice for the playoff bullpen.
With that being said, I do not think Miguel Socolovich or Sam Tuivailala should be excluded from this conversation. They have both put up solid numbers in 2015, although Mike Matheny has been hesitant to utilize them in high leverage situations. Tuivailala clearly has the most potential, with his near triple digits fastball and high strikeout rate, but he still needs to improve his control before he can be a reliable late-inning option.
The only other person who has the potential to shake up the Cardinals' postseason bullpen construction would be Adam Wainwright, who is trying to make an improbable comeback from the torn Achilles injury he suffered in April. Derrick Goold of the St. Louis Post-Dispatch has given a few updates on Wainwright's status over the last few weeks, and the latest we've heard is that he will check with doctors on Monday to see if he has progressed enough to work his way towards game action. I still think it is doubtful that Wainwright will return this season due to his future value to the team and the risk of re-injuring his Achilles. However, I will admit that it is quite exciting to imagine Wainwright back in the bullpen for another playoff run, nine years after his magical 2006 season.
Barring a miracle comeback from Wainwright, it seems likely that Mike Matheny will audition a few different relievers for the final bullpen spot over the next couple of weeks. Given the construction of the Cardinals' bullpen and the managerial style of Matheny, it is unlikely that the pitcher who earns this spot will pitch in high leverage spots in the playoffs (unless, of course, we are talking about the 9th inning of an elimination game with the score tied).
With the number of position players the Cardinals currently have on their roster, an argument could even be made that the team should carry an extra position player on the bench, given that a starting pitcher will already be joining the bullpen. This scenario is probably unlikely, though, given the fact that Mike Matheny and Derek Lilliquist often choose to carry an extra reliever instead of an extra bench bat. Still, the Cardinals have wasted roster spots in recent postseasons by having certain relievers basically go unused, so an argument can be made that having an extra pinch hitter would be the best use of the final roster spot.
Ultimately, this will be one of the many decisions that the Cardinals will have to make in the comings weeks with regard to playoff roster construction, and I will be fascinated to see how all these decisions play out.