The Milwaukee Brewers and Kansas City Royals lined up for a trade Saturday night, with Kansas City sending left-handed reliever Angel Zerpa to Milwaukee for outfielder Isaac Collins and right-handed reliever Nick Mears. The teams have yet to announce the deal officially, but it has been confirmed by The Athletic’s Ken Rosenthal. I can see the logic of the deal for the Royals right away, but I’m struggling to understand it for the Crew.
Zerpa kills left-handed batters but has had a platoon split his whole career, even after a reasonably successful move to the bullpen in 2023. Over his career, he has allowed a .282/.340/.470 line to righties, and his line versus righties was a little worse (.303/.356/.483) in 2025. He’s a sinker/slider guy who had one of the best groundball rates in the game last year at 63.7 percent, and since he moved to the bullpen, he’s been enough of a strike thrower to make that formula work even without a swing-and-miss pitch.
Angel Zerpa has struggled to make his changeup an effective pitch. (Charlie Riedel / Associated Press)
Zerpa’s slider has always had sharp downward break to it, but it doesn’t miss bats, possibly because he doesn’t have any deception in his delivery. His changeup has been a nonfactor in the majors, and it’s a below-average pitch at best, without much movement in any direction. The Brewers have had success helping pitchers get more run on their changeups, so I wonder whether they think they can do the same with Zerpa. Freddy Peralta, Brandon Woodruff and Jacob Misiorowski all have effective changeups that move more horizontally (relative to the average pitch) than vertically, and Zerpa is at a point where any improvement in the changeup will probably produce big marginal gains.
I don’t believe Zerpa can start, even if he gets that third pitch; there’s just no deception here, and he’s never had the control to start or the delivery to think he’ll find the control. He could be a better reliever than he’s been, however, if he’s not so vulnerable to righties.
Outfielder Isaac Collins made his MLB debut in 2024 at age 27, started 2025 on the Brewers bench, and eventually played so well he ended up a regular, with a .268/.368/.411 line for the season. He’s a very disciplined hitter, with strong walk rates throughout his time in the Colorado Rockies and Brewers systems, and posted a chase rate of 18.4 percent last year, putting him among the top 2 percent in baseball.
Collins is also a plus defender in left, with a below-average arm that keeps him from playing somewhere else. The Royals got absolutely nothing from their outfield last year, and particularly from left field, where Drew Waters and a few others combined for a .224/.291/.348 line Collins could easily top even if there’s some regression in his second big-league season — not that I think there’s a specific reason to expect it in his case. I wish he hit the ball harder, but if he had, he would have been in the majors some time before 2024. A left fielder who gets on base and plays plus defense without power is an unusual profile, but it was enough for Collins to accumulate a 2.6 fWAR/2.1 bWAR in 441 plate appearances last season.
Right-handed reliever Nick Mears comes from a very high slot with an above-average to plus slider. He improved his control substantially in the time he was with Milwaukee to turn himself into a capable middle reliever. He’s better against right-handed batters, but his platoon split is small enough that he can go full innings, with more power allowed to lefties last year but not the year prior. If there’s a difference between him and Zerpa, it’s that Zerpa might have some upside remaining with the addition/alteration of that third pitch, whereas Mears probably is what he is.
The Royals clearly benefit from this trade — Collins is easily a two-win upgrade over Waters, and Mears for Zerpa might be a wash.
I’m surprised the Brewers would make the trade, not just because it looks like a 2 WAR loss on paper, but because Collins’ OBP would have led the entire team if he’d played enough to qualify. (The same is true of Andrew Vaughn, who had 254 plate appearances as a Brewer.) They gave Akil Baddoo a major-league deal for next year, even though he hasn’t hit at all in the majors since his rookie year in 2022, although he did have a Collins-like year in Triple A. Otherwise, I don’t see who gets the playing time in left, and I certainly don’t see who’s going to pick up the offensive slack. This seems like a prelude to another move, but one in which the Brewers appear to have lost some value, too.