Let’s Find a Lefty Reliever for the Cardinals

After this week, it’s all but official that it’s time for the St. Louis Cardinals to start thinking about roster construction for 2019 and beyond. There are a lot of ways they can improve next season. One of the more obvious ways to improve moving forward is the bullpen, the rightful whipping boy du jour. Their bullpen xFIP this year is 6th worst in the game through Monday night’s debacle. Their Win Probability Added (WPA) is dead last at -3.95, and it’s not even particularly close to the second worst team (the Mets at -2.76). Since 2010, that’s 252nd out of 270 teams. It’s not quite historically bad, but it’s dreadful enough in a garden variety way. The biggest driver of that horrible performance has been their left-handed relief.

To accentuate how bad Cardinals’ lefty relievers have been this year, their xFIP from lefty relievers is 5.57 through Thursday. That’s the worst in the game this season. It’s the worst for any team with 35 or more innings from lefties in Fangraphs’ split leaderboard since 2002, and the leaderboard does not go back further. In other words, it’s the worst left-handed bullpen by xFIP that you can readily find in recent history. That being the case, it’s an obvious area to address. It’s an area where even a decent addition would make up significant ground.

Obviously, this type of move can happen at any point. The approaching trade deadline is one of many windows for the front office to make an acquisition. Since we’re at the trade deadline, I’m going to focus purely on arms that might be available now, and not after the season. What kind of lefty relievers are out there?

We’ll start with a list of all lefties who have amassed 35 total innings or more out of the bullpen from 2017 until today. There are 75 such pitchers after we remove Brett Cecil and Tyler Lyons. We can also limit this by removing any pitcher for contenders. Today, that means any pitcher for Boston, Cleveland, Houston, the Yankees, Seattle, and Oakland in the American League. In the NL, the list includes the Cubs, Dodgers, Nationals, Milwaukee, Arizona, Philadelphia, and Atlanta. Colorado is right on the cusp with approximately 24% odds, but I’ll leave them in for now. Stripping out lefties for contenders whittles down our list to 42. We can also omit current free agents Enny Romero, Josh Smoker, and not-quite-free-agent Kevin Siegrist (technically he’s a Pirate but this is not the move anyone wants). Mike Minor is in here and doesn’t belong, having moved to the Rangers’ rotation. We are now down to 38.

Rentals make no sense for the Cardinals, so let’s remove any pitcher whose contract expires at the end of this season. That gets us down to 30 lefties under contract through 2019 or beyond, playing for non-contenders. We can also eliminate any pitcher currently on the disabled list, meaning Chris Rusin, Vidal Nuno, Richard Bleier, and Mike Dunn are off the table. Jose Torres is suspended via MLB’s domestic violence policy. That leaves us with 25 potential lefties. And finally, the Reds and Pirates are almost certainly not going to trade usable long-term assets to the Cardinals, nor do the Cardinals want to give those teams the same in return. We can eliminate Felipe Vazquez, Steven Brault, Amir Garrett, and Wandy Peralta. Now, we’re down to 21 potential trade targets.

Before we start eliminating lefties based on poor performance by traditional metrics, I want to see if any of them have underlying skill that hasn’t led to positive results. Specifically, I want to see if any of them have gained velocity over the last year, or are being punished by bad luck on contact. We’ll calculate the difference in their average velocity from 2017 to 2018, and also include their wOBA-xwOBA. Looking at velocity, there are no major leaps, although four pitchers have gained half a mile per hour or more. We’ll give them extra consideration. There are also four that have lost more than two miles per hour. They get a big red flag. Using wOBA-xwOBA, no pitchers appear especially unlucky, but four have yielded a wOBA more than .030 lower than their xwOBA. Those four will get a red flag as having some luck swing in their favor.

Next, let’s eliminate any reliever with both a FIP and an xFIP over the last two seasons over 4.25, with one exception, which I’ll explain later. We are now down to 14 pitchers. Four of those have been flagged because of a drop in velocity- Jake McGee, Luis Avilan, Tony Watson, and Jace Fry. One more, Ryan Yarbrough, has pitched into some good luck this season. Given that he plays for the Rays (who struggle to complete deals with the Cardinals) and he’s under contract through 2023, I think it’s safe to eliminate him. We should eliminate McGee, Watson, and Fry as well, but I’m going to leave Avilan alone. His velocity dip is alarming- 3.6 miles per hour on average- but a large part of that is due to what appears to be a revised curveball this season. He’s throwing it with significantly greater vertical and horizontal drop this year, at a lower velocity. His fastball has slipped about a mile and a half per hour, but it hasn’t harmed him. In fact, his peripherals still look great. In short, Avilan stays, bringing us to 10 potential targets. Here’s what we have remaining, sorted by 2017-2018 FIP. I’ve also included how many more years they’d be under contract.

There’s plenty to work with in there, but we should eliminate a few more. Flynn and Stumpf have really struggled and have some ugly peripherals. If you’re going to take a gamble on them, you might as well just stick with your own internal gambles. Ty Blach has some prospect prestige and the Giants have floated him back and forth between the bullpen and rotation. They aren’t likely to move him just yet. Alvarado and Bummer are each under contract for four more years, so I’m not sure they fit this model, though either would be just ducky.

That leaves us with five options- Luis Avilan, Robbie Erlin, Taylor Rogers, Alex Claudio, and Jose Alvarez. Claudio’s K rate is terrifyingly low. He offsets some of that with a tremendous groundball rate and rock-bottom homerun and walk rates. Still, it seems like a shell game destined to be exposed at any time. Since we aren’t trying to find good contingency plans, but rather guys that might excite us a little, I’ll omit him.

Of the four remaining, Avilan has the best track record. Alvarez is the most steady, although it’s steady mediocrity. Erlin is intriguing, albeit a bit of a gamble, and Rogers is downright exciting, as LOOGYs go. Erlin is the most platoon-neutral, pitching more effectively against righties than lefties, whereas Rogers is the LOOGYest. For three of them, they play for American League teams, thereby opening up the potential for Jose Martinez as a maximized asset/building block for a trade. To be clear here, I’m not suggesting that Martinez should bring back a LOOGY alone (far from it). Merely that he’s a potential starting place.

The bar for an upgrade here is low, but three of these lefties (Erlin, Rogers, Avilan) represent more than that. They offer cost-controlled stability in the final flaming ashes of the 2018 season, plus the 2019 season (and in some cases, 2020). If the Padres, Twins, or White Sox are willing to deal outside of the constraints of traditional deadline buyers and sellers, the Cardinals should make a deal for one of them. Any would make a fine pairing with Tyler Lyons and Austin Gomber entering next season.