Playoff contenders continued to overhaul their bullpens on December 13. The Brewers and Royals swapped relievers, as left-hander Angel Zerpa is headed to Milwaukee for Nick Mears. Isaac Collins, a sparkplug for the Brewers last season, is also headed to Kansas City alongside Mears.

The Brewers’ Return

• RP Angel Zerpa (58 K, 22 BB over 64.2 IP)

The Royals used Angel Zerpa a lot over the last two seasons. A 26-year-old left-hander, Zerpa threw in 129 games over the last two seasons, as well as five postseason games for Kansas City. These past two years marked a change for Zerpa, who was primarily a starter as a Minor Leaguer, up until 2023.

Zerpa didn’t put eye-popping numbers, as far as some of the advanced analytics were concerned. He ranked 180th out of the 221 relievers in wOBA (.330) this past season (min. 30 GP). The left-hander also ranked among the league’s worst in Whiff% (16.4%).

However, one can see why Zerpa would be valuable, particularly to a team like the Brewers.

One, he can throw hard. Zerpa’s two fastballs, a four-seamer and sinker, averaged in the mid-90s this past season. Zerpa will use his sinker against lefties and righties. His four-seamer, as well as his changeup, are mainly used against right-handed hitters.

He’ll also use a slider with good breaking action and a pitch that generates ground balls.

That sinker/slider combo works very well against left-handed pitching. Last season, opposing same-sided hitters batted .225/.301/.343 (.644 OPS) off Zerpa. Right-handed hitters (.839 OPS) fared better.

Zerpa ranked among the best groundball pitchers (63.7%) in the game.

The Royals’ Return

• OF Isaac Collins (.263/.368/.411, 9 HR over 130 GP)
• RP Nick Mears (46 K, 13 BB over 56.2 IP)

The Brewers struck gold with Isaac Collins, a 28-year-old switch-hitter who played his college ball not too far from Kansas City with Creighton. Collins made his MLB debut in 2024, five years after the Rockies drafted him in 2019.

He played an important role for the Brewers last season. Collins finished the year with a .779 OPS, 16 stolen bases, and 34 extra-base hits. He spent most of the year in left field and played overall defensively. Collins posted a +4 overall Outs Above Average last season.

However, what made Collins truly valuable was his eye.

Collins finished the year with the 21st-highest walk rate (12.9%) in the Majors among players with 350+ plate appearances. He won’t hit for a ton of power. On the other hand, he won’t expand the zone too much.

The other piece to this deal was Nick Mears, who ranked significantly better in the wOBA (.266) department. Mears, like Collins, was a member of the Rockies’ organization at one point. Milwaukee acquired him in July 2024 for two pitchers.

Mears is a three-pitch pitcher with a mid-90s fastball, slider, and curveball. Low groundball pitcher. However, a high chase rate pitcher.

Analysis

The Brewers had a lot of outfielders on the 40-man roster. Before the Collins trade, there were nine, including Jackson Chourio, Christian Yelich, Sal Frelick, Blake Perkins, and recently-signed Akil Baddoo.

On the same token, the Brewers had some lefties on the 40-man, including Sammy Peralta, Aaron Ashby, and Jared Koenig. However, the 6’0” lefty Zerpa is a little different. For one, he’s an extreme ground-ball pitcher who is mainly a sinker/slider pitcher, and a little bit of a different look than Koenig, a 6’5” lefty who sprinkles in a curveball and cutter.

And as for the extreme ground-ball lean, that may fit in very well with a Brewers team that has a good defensive infield.

The Royals, meanwhile, get a toolsy outfielder in Isaac Collins, who will look to provide more outfield production for a Kansas City team that needs it.

For one, Collins gets on base. The Royals hoped that Jonathan India would stabilize the top part of that lineup, as he was known for getting on base as a Red. Collins can certainly help turn the page, whether it is at the top of the Royals’ lineup or at the bottom to set up that group of Bobby Witt Jr., Salvador Perez, and Vinnie Pasquantino.

Plus, Mears isn’t a bad arm, either.

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