Cardinals’ bullpen struggles prove volatility was always inevitable

Oh, the bullpen. St. Louis Cardinals fans are already at their limit with this year's group, and I don't blame them!

At the same time, we can all acknowledge that for how bad it has been thus far, it's also been about as weird a start to the year for that group as possible.

The bullpen has certainly not done its job, but there have also been, call them unlucky or unfortunate, situations that they've found themselves in that have made it hard to compete. But honestly, we should have expected things not to be smooth out of the gates.

If there's anything we know about bullpens, it's that they are about as volatile of units as any in the game of baseball, so seeing the Cardinals' group go from elite last year to a true question mark less than a week into the regular season is pretty on-brand, and there are a number of reasons for that.

Turnover, regression (both positive and negative), batted ball luck, and so many other things contribute to the Cardinals' bullpen volatility

1. Turnover

For the first half of the 2025 season, the Cardinals could consistently turn to a strong core of Ryan Helsley (3.00 ERA, 36 G), Phil Maton (2.35 ERA, 40 G), JoJo Romero (2.07 ERA, 65 G), Kyle Leahy (3.18 ERA, 61 G), Steven Matz (3.91 ERA, 30 G), Riley O'Brien (2.06 ERA, 42 G), and Matt Svanson (1.94 ERA, 39 G) to get outs for them on a consistent basis. Now, less than half of those names remain in the bullpen.

Losing Helsley, Maton, Matz, and moving Leahy to the rotation was going to be hard to replace. It just was. Even with how good Svanson, O'Brien, and Romero were last year, it's hard to go from a bullpen that had seven legitimately good options to go to each night to trusting just a few arms and seeing what the rest have in store.

Sure, the Cardinals brought in Ryne Stanek this offseason, but that's far from replicating what they had in the tank last year. I'm not saying the Cardinals were wrong to build their bullpen the way they did this offseason; I just think it's fair to say it was unrealistic to believe they'd be the same unit again.

2. Regression (both positive and negative)

One of the few things you can rely on year to year in baseball is the fact that you actually have very little idea how good your bullpen will be any given year. It's the weirdest truth that you can count on. It feels like any given year, an elite reliever can turn into a pumpkin on the mound, and some random arm that had been cast off by three or four other teams ends up becoming a high-leverage option.

The teams that manage to consistently construct good bullpens just happen to pull the right levers and turn the right dials. They take just enough "flyers" on guys while having the right mix of young and veteran arms. Oh, and the manager deploys them well.

The Cardinals have done that with the best of them the last two seasons. They certainly could end up having a great bullpen again in 2026, but expecting relievers to just be good again is never really a given in today's game.

3. Batted ball luck

Looking specifically at the Cardinals' bullpen performance in the first few games of the season, it's hard not to get the sense that they have been extremely unlucky.

Whether you look at xBA, FIP, or batting average on balls in play, the Cardinals' bullpen had been giving up hits, and ultimately runs, at an unsustainable level.

Positive regression is coming for the bullpen, but there are certainly a few things they could do to help with that. First, swing and miss is going to be their best friend. Balls in play can work against you, even if you induce terrible contact (see Chris Roycroft and Matt Svanson), but swing and miss is...well, a swing and a miss. The more they can miss bats, the better their chances are of limiting damage. Not rocket science!

Second, and far from a genius thought, once again, but limiting the walks they give up is also going to really help lead to more positive results. Through four games, the Cardinals' bullpen has walked 11 batters in 17 innings, tied for the fifth most in baseball. Not good! They have the third-worst K/BB ratio (1.06) in the game as well, illustrating just how rough it has been.

I have no doubt the Cardinals' bullpen will be better in the coming weeks and months, but how much better is a real question. It's been the main limiting factor of their unfield success so far, and barring two incredible comebacks, the Cardinals would be 0-4 right now due to the unit's troubles. They've got to get the train on the tracks fast, or it will be tough sledding for St. Louis almost every night.