Will the Brewers 2026 rotation include lefties, and does that matter?

Harrison made an early attempt yesterday to predict the Opening Day 26-man roster, and it got me thinking about something that has come up in conversations lately, and that is whether the Brewers will have left-handed pitchers in their starting rotation. That also led to the question of whether that is indeed the case business whether there were left-handed starters. I was curious about both questions, so let’s first do a quick recap of the pitching staff options and their craft, and then look at the league-wide splits.

As Harrison points out, the Brewers have 13 players on their current 40-man roster who could reasonably start (and let’s assume we’re talking about actual starts, not ‘opens’) in a game for the Brewers next season. I’m going to rank them in a sort of depth chart order, along with their R/L handedness:

If the Brewers have taught us anything over the past two years, it’s that we shouldn’t expect them to stick with a five- or six-man rotation for long. Injuries can happen, players need rest, etc. So the fact that I’m not putting a lefty on the list until we get to number seven – Gasser – in no way suggests that I don’t think lefties will start.

But there are real questions about whether any of these lefties will figure into rotation plans, whether that means early in the season or not at all.

Aaron Ashby and DL Hall have both pitched almost exclusively in relief over the past two seasons, and both have injury histories (particularly Hall) that could make the Brewers wary of using them in the rotation. Ashby also asks a confusing question: He’s been so valuable in an old-fashioned “firefighter” role that the Brewers might want to keep him there. What’s more valuable: the reliever who has thrown 95 innings in 57 games with 10.3 K/9 and some of the best stuff in the league over the last two years, or a starting pitcher who has to rely on that to move forward?

Hal could be a different story. When the Brewers acquired him along with Joey Ortiz for Corbin Burnes, they were certainly thinking of him as a starter. Hall was ranked in the top 100 for several years when he started exclusively in the minor leagues, but pitched in relief when he got cups of coffee with the Orioles in 2022 and 2023. Injuries have marred his career in Milwaukee, but he started 14 games with Triple-A Nashville in 2024 and made a pair of spot starts last season, even though only 10 of his 33 major league appearances with the Brewers were starts.

The injuries could force the Brewers to move Hall into a long-term bullpen role, but since Hall hasn’t been nearly as good as Ashby out of the bullpen, it likely means the Brewers would prefer to move Hall ahead of Ashby in the rotation. There is a small matter of money hanging over Ashby’s head; after signing an early career extension with the Brewers, Ashby is owed $5.5 million this season and $7.5 million next season, and the Brewers have option years in 2028 and 2029 for $9 million and $13 million. Those are reasonable numbers for a good pitcher — even a reliever — but the Brewers aren’t in the habit of spending that kind of money on relief pitchers. Is there any chance they’ll want to put Ashby in the rotation to try to better justify the money they’re spending?

Maybe… but it doesn’t seem like the smart move to box Ashby in if it’s not the best move for him. Maybe the Brewers will try to take him out of the rotation this spring and see how things go, with a “cancel” button at the ready. But if he’s more valuable to the team as a reliever, they should use him that way. Expect trade rumors to surface if that’s the route chosen – maybe not this year, but soon.

Gasser appears to be the most likely lefty option to start games for the Brewers this season. He’s not far down the depth chart, and he made a return to the rotation late last season for a pair of starts (and two relief appearances in the playoffs). Gasser likely wasn’t at full strength at season’s end as he worked his way back from Tommy John surgery he underwent in June 2024. A full offseason and full spring training should have Gasser back at full strength, and while I think the Brewers probably favor the top five guys on my depth chart above, I could see Gasser partially edging out Henderson at sixth. because he offers something different as a southpaw.

Another wrinkle here is that it’s conceivable that the Brewers were so intrigued by the bullpen version of Chad Patrick, who broke through the 2025 postseason, that they could keep him in that role — especially if, say, Trevor Megill leaves and there’s a big opportunity for someone new to the pen. If the Brewers think having a lefty in the rotation is important, they can certainly start the year with Patrick in the bullpen and Gasser in the rotation.

However, after Gasser, Ashby and Hall, there isn’t much to look at. Matt Arnold said some things about the potential of using new signing Ángel Zerpa as the starter… but this feels like posturing to me. I would be surprised if Zerpa was used in the rotation at all this season.

However, the bullpen has more options. Ashby and Hall have already been discussed, and there is a real chance that Zerpa will immediately fill a role with a lot of influence. Jared Koenig is still around, too, and he’s proven enough over the past few seasons that he’s rightfully become one of Pat Murphy’s favorites. Milwaukee also still has Rob Zastryzny on the roster, and while he seems to be an afterthought in most of these discussions, he has done nothing but outs as long as he’s been in a Brewer uniform: It’s a small sample, but in 29 2/3 innings over the last two seasons, Zastryzny has allowed just seven earned runs (2.12 ERA). It’s true that Zastryzny’s FIP is lagging (4.09), but he is certainly an option.

Sammy Peralta is another bullpen option, but given the other choices available, his lack of experience and his existing minor league option, it seems likely he will start the season in Triple-A.

Regardless, Ashby, Hall, Koenig and Zerpa will all likely be on the roster to start the season — Hall could potentially face a numbers crunch, and he still has one option left — giving the team plenty of matchup flexibility in the bullpen.

Well, a little. Managers don’t go out of their way to get the right pinch-hitter or the right-left-handed pitcher into the game at the right time for no reason. In 2025, the league had a .725 OPS against righties and a .704 OPS against lefties. Situationally, left-handed hitters struggled more against left-handed pitchers than any other type of matchup. Baseball Reference regulates the league somewhat by putting this on an OPS+ scale (on their breakdown page this is called tOPS+); Basically it breaks down as follows:

RHP vs. RHB: 96 tOPS+
RHP vs. LHB: 108 tOPS+
LHP vs. RHB: 101 tOPS+
LHP vs. LHB: 85 tOPS+

So it’s pretty clear that left-handed pitchers create favorable matchups (and hardly create unfavorable matchups, even when the pack is not in their favor).

But…I also believe that these differences aren’t enough to justify not just using your best starting pitchers. In certain left-handed games, especially in the postseason, it would certainly be an advantage to have one or two lefties available for longer outings, but the pitching rotations are so thrown into disarray by the postseason that it doesn’t really matter who is there in the regular season. My advice to the Brewers would be to just use the five pitchers who appear to be the best five at any given time. Worry about splitting the pack later.