The Cardinals' pen has been a mess this season. That's not exactly ground-breaking news to those that read this site. Seung Hwan Oh has been an absolute delight, and Matthew Bowman has been decent. Basically everyone else is in the "mess" category.
Tyler Lyons has been part of that everyone else, but he did it in a unique way. Here's the current top 10 among all qualified relievers in HR/FB%:
Lyons has the second highest HR/FB rate in the game. He's pitched pretty well in the other two true outcomes though. Of course, he's no Andrew Miller. Miller's 1.5 WAR is fourth among relievers this year despite that eye sore of a HR/FB rate, and that's kind of amazing.
Getting back to Lyons, it's pretty obvious that the homer issue is a big part of why Mike Matheny has only used him as a long reliever. This is typical Mike Matheny, putting a lot of emphasis on too small of a sample size. That's a problem for the analytical fan (a "fanalyst", if you will), as it takes about 400 fly balls to get a reliable estimate of HR/FB rate. Lyons' 32 fly balls in 2016 falls more than an order of magnitude away from that. For his career he has an above-average HR/FB rate at 15.4%, but that's just 188 fly balls, still less than half the way there. That might be enough to say he's slightly more homer prone than average, but nothing more.
It's a shame too, as that homer rate gives Lyons an above-average FIP on the year. As you're probably aware, FIP (fielding independent pitching) is calculated based on a pitchers' strike outs, walks, and homers; things that are not influenced by the defense and the noise of balls in play.
xFIP on the other hand, as you're also probably aware, replaces homers with an expected home run total based on a pitchers' FB% and the league average HR/FB rate. Because it takes a while to get an idea of a pitcher's true HR/FB rate, xFIP is more predictive in smaller samples. Lyons ranks much better by this measure:
You probably don't think of Lyons as the second best reliever for the Cards this year, but by xFIP at least, he has been. Interestingly, even by FIP, Lyons has been just as good (or bad) as Siegrist, and he's been much better by xFIP. Still, Siegrist continues to get the ball in much higher leverage situations.
The last two columns are leverage index stats which measure the average leverage index of all situations the pitchers been in (pLI) and the average index just when entering the game (gmLI). A score of 1 means the reliever experienced average leverage, with lower or higher than one indicating lower or higher than average leverage. The only pitchers who have pitched with less leverage was Samuel Tuivailala and Seth Maness. The former was clearly called up just so the Cardinals could have a fresh arm while Siegrist was on the DL, and the latter is clearly broken.
I've mentioned Matheny's dependence on small sample sizes before, and have grown to begrudgingly accept them, if only for the benefit of my blood pressure. Doling out playing time based on recent production, even if it lacks repeat-ability, is better than having "Mike Guys" and "not-Mike Guys", which was a common criticism against Matheny before this year. At the least, the players can accept playing or not playing based on how well they're performing.
In Lyons' case, I figured once he had a string of appearances where he wasn't getting shellacked, Matheny would promote him to more important situations. However, Lyons has been much better in the last 30 days, and still isn't getting any love:
Lyons actually has a lower FIP than xFIP over this time frame, thanks to running a below-average HR/FB rate. You could make a pretty strong case that Lyons has been the team's best reliever over the last 30 days, but at the very least he's been one of the three best, with Oh and Bowman. Still, Maness and Tui are the only relievers used in lower leverage situations than Lyons. Of course, Kevin Siegrist has an extra small sample due to the DL trip, but he's received the highest leverage situations despite walking as many as he's struck out over the last month.
Even more confusing is that Trevor Rosenthal has the second highest game leverage, despite being kicked out of the closer's role on the 25th of last month, pretty early in this 30 day stretch. That is some pretty bad in-game strategy on Matheny's part. Jonathan Broxton has been the bizzaro Lyons, both for the year and the last 30 days: absolutely horrid K% and BB% numbers that are saved by an exceptionally low HR/FB. That seems unlikely to continue.
I don't want to get to wrapped up in the last 30 days. That's a short amount of time to evaluate anyone, let alone a reliever. However, Lyons has been above-average for his career. He's been above-average in terms of xFIP in 2016 as well. He just had a bit of a homer problem to start the year. Even if you could somehow justify that the homer problem was real, the last 30 days has seen a marked improvement.
Getting back to the gap in Lyons' FIP and xFIP, it's even wider when looking at his numbers against right-handed hitters. Here's his handedness splits for the year and for his career:
In 2016, he has better strikeout and walk numbers against righties than against lefties. That's not the case for his career though, so I wouldn't expect that to continue. That is an unsightly HR/FB rate against righties, but it's also only 19 fly balls, or less than 5% of the way to a reliable sample.
Lyons' xFIP split for his career and 2016 both point to him being a decent candidate for facing hitters from each side of the plate. While Lyons is a Four-seam/slider guy against lefties, he breaks out the change-up against right-handers, which has a 37% whiffs/swing on the year courtesy of Brooksbaseball.net. Right-handed hitters are also missing curve at the same rate, 37%. That's more often than left-handers are swinging and missing at it (29%) which is atypical since breaking balls are usually more effective against same-handed hitters. For his career, Lyons' slider has a 40% whiff/swing against lefties.
His 2016 HR/FB rate has always looked fluky, and after a month of finally not giving up a bunch of homers, it looks even more fluky. Meanwhile, the bullpen is still imploding on a way too often basis. How much longer will Rosenthal, Siegrist, and Broxton continue to perform poorly and still be handed more important situations than Lyons? In a Wild Card race that could easily come down to a difference of a game or two, the change already should have been made. Hopefully, it comes soon.