When it comes to building a bullpen, there is truly no winning. A decent majority of Cards fans will see the failures of the high-priced relievers of the past and not want to sign them. A decent majority of Cardinals fans want them to fix the bullpen. A decent majority of fans get mad when the solution to the bullpen is a random guy who wasn’t good last year. Somehow all these things are true. Fix the bullpen, but not with random guys and not with high priced relievers.
The cost of a reliever on the free agent market (or on the trade market) is directly proportional to the upside and risk that they bring. A “moderately” priced reliever who may be in between my two options usually carries a moderate amount of upside with a reliever amount of risk. And if you’re going that route, your Joe Kelly route if you will, why not just get the cheap version, the version you can and will easily release if they suck? (It’s here where I share that I am completely mystified by all the fans wanting Joe Kelly back, so I’m just going to chalk that up to nostalgia)
If you were to fill out the outer edges of the bullpen with random, inexpensive guys who you hope can have a good season, Nick Wittgren is pretty much exactly the kind of guy you sign. He has relatively stable advanced stats from year-to-year, but since he’s thrown over 50 innings in just three of his six seasons, his ERA has predictably fluctuated. Last year was one of the years it fluctuated into a career worst ERA, which you could take as a negative or you could take it as opportunity for the Cardinals. Obviously the Cards saw opportunity.
And a statement such as “has only thrown over 50 innings three of his six seasons” should probably be clarified for those worried about injury risk. One of those seasons was 2020, when the season was shortened (and he also pitched in 25 of the 60 games wow), one of those seasons was 2018 when he had a right middle finger contusion, spent about two weeks on the IL, and while on his rehab assignment, was suddenly on the outside looking in for the bullpen and got optioned to the minors until September (he had a 2.94 ERA in the majors FWIW), and in 2017 he did actually miss the last two months to injury. Some amount of injury risk, but pretty mild for a pitcher actually.
Born in California, Wittgren actually grew up in Indiana and went to Parkland College, a community college in Champaign, Illinois, upon graduating from high school. After a year there, he transferred to Purdue and functioned as their closer for two years. He was drafted after his junior year by the Miami Marlins in the 9th round of the 2012 MLB Draft. So Wittgren has always been a reliever as a professional.
He obliterated the lower minors, like the minors did not even present as kind of a problem for him until he reached AA at 23-years-old in 2014. He had a 1.46 ERA in short season A with a 1.18 FIP and 33.3 K%, a 0.83 ERA in High A with a 1.97 FIP and 27.6 K%, and he struck out 13 of the 20 batters he faced in Low A. His Ks fell to 20% at AA, and he mostly relied on not walking batters with a 5% BB rate. His numbers were unexciting but respectable, with a 3.55 ERA, 3.40 FIP, 3.28 xFIP. He spent most of the next season in AAA and improved upon those numbers - 25.5 K%, 3.2 BB%, 3.03 ERA, 3.23 FIP, 3.34 xFIP.
Once he got promoted to the majors, he mostly settled into the AA version. The one who didn’t really strike many out and didn’t walk people. This version typically works better if you also get groundballs, which he didn’t. He did strike out more batters in his second season, but also walked more and got even less groundballs. I’m not really sure what happened in 2018, but he became kind of a groundball pitcher (career high 46%), but also walked 10% of batters and he has not even come close to that number in any other year. Thanks to a career low 2.7 HR/FB%, he had a 2.94 ERA and 3.13 FIP (4.56 xFIP).
I think the Marlins soured him after 2017 though. Like I said above, he got injured and then he stayed in the minors until September during that 2018 season. His AAA stats aren’t great, so maybe that finger contusion really affected his pitching. But the Marlins traded him for... not really anything. It wasn’t a salary dump because he wasn’t making any money, so let’s call it a roster dump. He was traded for a 27-year-old reliever who never made the majors and whose career appears to be over. It feels like they didn’t release him because this trade was more convenient, instead of having to also sign minor league bullpen depth.
With Cleveland, it seems like he took a slightly different approach than with the Marlins. His lowest K rate in Cleveland is as high as his highest K rate with the Marlins. But his BB rates were also lower than all but one of his Miami years. The price for this appears to be a willingness to accept home runs as part of the package. He posted HR/FB% of 16.7%, 17.4%, and 24.5% with Cleveland. So he refined his K/B numbers, but the last step is just not allowing homers.
He’s in the right park. Cleveland isn’t really a bandbox, but it is slightly more prone to homers than average. According to Fangraphs Park Factors, Progressive Field is a 101 with 100 being exactly average by homers. Anything above is more offense than average, anything below is less. Busch Stadium, by comparison, is a 93 for homers. Only four teams are more favorable to pitchers than that. Wittgren’s lone weakness is homers. He’s in the exact right park to minimize that weakness.
I may not even need to use speculation. LoanDepot Park is also a pitcher’s park, and also a park that is favorable to pitchers. In fact, it’s even more favorable than Busch Stadium. The Marlins are one of the four teams more favorable to pitchers than the Cards. They are a 91 on that scale. With the Marlins, Wittgren’s HR/FB% was 7.8%. With the Guardians, it’s 19.9%.
Now, there may be evidence that Wittgren with the Indians and Wittgren with the Guardians are not really the same pitcher, supported by the K/BB numbers. He also just in general hasn’t pitched many innings in his career with just over 270 career innings. There is reason to believe his HR/FB% would drop naturally even if he stayed in the same park. A starter with a season and a half worth a data would not have a trustworthy HR/FB% so just because a reliever did it over six years does not make it any more trustworthy.
The middle ground between the Guardian years and the Marlins years are his career numbers. His FIP is nearly the same as his xFIP. He has a career 4.03 FIP to 4.07 xFIP. We can have optimism about his HR/FB% at Busch Stadium certainly, but his career 13.5 HR/FB% is probably what we should prepare for. He does have to play in Milwaukee and Cincinnati after all.
But the biggest reason for optimism is actually a stat I rarely use, SIERA. SIERA stands for skill-interactive Earned Run Average. It functions like FIP but factors in the type of ball in play. Not the quality of contact (except if something is defined as a line drive I suppose), just the type. His career SIERA is 3.72. His career ERA is 3.75. Again, not necessarily something we should take as gospel due to the lack of innings in his career, but it’s the closest to his actual ERA.
What was his SIERA last year? 3.57. His xFIP was also 3.63. But due to the homers, his FIP was 4.84 and his ERA was 5.05. Again, take out the homers, Wittgren is a solid reliever, definitely a bargain for $1.2 million. I will mention though, because I must, that even though his career SIERA is pretty close to his actual ERA, in most seasons, his SIERA is wildly different than his ERA. 2021 is one example. In 2018, he had a 4.20 SIERA and 2.94 ERA. They did come pretty close in that shortened 2020 season but that’s about it.
Seems like an easy gamble that Wittgren’s home runs allowed will improve at Busch Stadium, a stadium we’re all too aware of as a home run-killing stadium. Wittgren is literally the kind of guy we should be signing and if it means we’re moving away from the Andrew Millers, that’s great news for the future (and hopefully they’ll spend it on something else - in the future at least, I’m not expecting more this year)