Grading the Milwaukee Brewers' Caleb Durbin trade with the Red Sox

The Milwaukee Brewers entered the 2025-26 offseason in a strange spot. The team was coming off of their winningest regular season in franchise history, during which they won 97 games and earned the top overall seed in the postseason. However, a sweep at the hands of the Los Angeles Dodgers in the National League Championship Series left fans wondering if the Brewers' roster was in need of some major additions during the offseason to put an end to their World Series drought in 2026.

However, the Brewers aren't the type of team to look just at the year ahead and neglect the seasons that follow. Doing so is the kind of short-sighted roster strategy that often leads to extended periods of non-competitive teams. Rather, Milwaukee always keeps an eye on the future, knowing that if they want to continue having chances to advance to the World Series, they first need to field a consistently competitive roster that reaches the postseason time and time again.

As a result, the Brewers' offseason strategy, brought on by their inability to simply fill their roster with free agents in future seasons if they elect to trade their controllable pieces for short-term improvements, has looked similar to other winters under the guidance of President of Baseball Operations Matt Arnold. It's been filled with opportunistic trades that turn positions of strength or potential regression candidates into some of the most valuable players in today's game: young, controllable starting pitching. The most recent trade being this morning's six-player swap in which the Brewers sent Caleb Durbin, Andruw Monasterio, Anthony Seigler, and a Competitive Balance Round B draft pick to the Boston Red Sox for left-handed pitchers Kyle Harrison and Shane Drohan and infielder David Hamilton.

Arnold reiterated the importance of adding these types of pitchers to the Brewers' organization on a Zoom call with team media members this morning, saying, “Our ability to add multiple arms, young arms, controllable arms, is something that's really exciting for us when you talk about the addition of guys like Sproat, plus Harrison, plus Drohan. The combination of adding those guys is really exciting."

Controllable pitching has become the most coveted asset in baseball, and for a good reason. Average starters on the free agent market right now are consistently earning eight-figure deals. Milwaukee fans may be shocked to learn that former Brewer Adrian Houser is set to earn $11 million in each of the next two seasons. The difference between that salary and the one that Harrison and Sproat will make during the next few seasons -- less than $1 million -- is substantial, especially considering each could realistically be a more effective starter than Houser. It's a market inefficiency that the Brewers are exploiting, and it should change the way fans view this shocking deal with the Red Sox.

Value of controllable starting pitching too much to overlook in Brewers' six-player swap with Boston

Caleb Durbin is certainly a valuable baseball player -- there's a reason the Brewers traded Devin Williams for him just over one year ago. His defensive acumen and baserunning ability give him a high floor that is bound to make any offensive struggles that could be forthcoming look less severe. However, the value of a utility infielder simply doesn't compare to the value of a left-handed starting pitcher. For that reason, while much of the baseball world ponders why the Brewers' front office would trade a Rookie of the Year finalist before his sophomore season, my inclination is to give Milwaukee a favorable grade for their most recent trade.

Brewers grade: B
Red Sox grade: C+

The Brewers received not one, but two controllable left-handed starters who either just started their big-league careers or are on the cusp of doing so. As often mentioned during the Freddy Peralta trade saga, adding that type of pitcher is no easy task -- teams aren't exactly itching to get rid of their young starters. For the price of three utility infielders -- a net of two when you consider Hamilton's inclusion -- and a draft pick, which should not be overlooked, that's an impressive haul to land. Let's break it down starting with Boston's return.

Caleb Durbin

Durbin had an impressive 2025 campaign; that much should not be discredited. However, there's reason to believe that the Brewers just sold on the young third baseman while his value was at its peak. On the surface, Durbin slashed .256/.334/.387, good for an OPS+ of 101 that deemed him just barely better than league average. While it's certainly possible that his batting average and on-base percentage stay where they are, expecting Durbin to improve or even maintain the slugging percentage that he posted in 2025 is a risky bet.

The 25-year-old infielder's underlying metrics tell a story of a player who was able to boost his power numbers by relying heavily on pulling balls in the air. It's by no means a bad strategy -- Durbin out-performed his power metrics considerably in 2025 -- but it is an unsustainable one. Once pitchers are keen to Durbin's desire to pull the ball in the air, they can change their sequencing strategy to prevent him from doing so. With an expected slugging percentage in the 16th percentile, an average exit velocity and hard hit rate both in the 4th percentile, and a bat speed in the 6th percentile, the odds of Durbin repeating his double-digit homerun mark in 2026 are low.

Let's say a modest amount of regression sets in for Durbin, and he settles into the 90-95 OPS+ range as a hitter. With his baserunning and defensive skills, Durbin can still be a productive big-leaguer, but maybe not the needle-mover that you would expect from an NL Rookie of the Year finalist.

Andruw Monasterio

Monasterio has been a key presence in the Brewers' clubhouse over the last three seasons. Not only is he a great teammate, but he's willing to do whatever it takes to help his team win. Since his rookie season back in 2023, when he was called upon in an everyday role at third base for much of the season, Mona has seen his plate appearances decrease in each of the last two seasons.

As a utility infielder, who can man a corner outfield spot if necessary, Monasterio is certainly still a valuable addition, especially given his three minor league option years, but it's difficult to see him carving out a big-league role on the Red Sox unless Boston loses several players above him on the depth chart to injuries.

Monasterio's time in Milwaukee was fun, and he brought many good memories to Brewers fans, but his inclusion in this deal doesn't change the calculus of the trade too severely, especially since Milwaukee is acquiring a similar player in David Hamilton in return.

Anthony Seigler

Seigler is an interesting inclusion in this deal, simply because he's the third utility infielder that Boston is acquiring in the trade. After signing a minor league contract with the Brewers last offseason, Seigler earned a brief opportunity in Milwaukee, appearing in 34 games during his rookie season last year. Though he certainly possesses a great deal of versatility, and his Triple-A numbers were strong, his offensive potential is capped by a lack of power, making him another high-floor, low-ceiling player -- the type of player the Brewers have shown an ability to manufacture out of thin air.

Like Monasterio, Seigler will have a tough time carving out a role on Boston's big-league roster, but both are immediately added to the Red Sox' 40-man roster seeing as they were members of Milwaukee's 40-man prior to the trade.

Though Monasterio and Seigler may have had a small role on the Brewers' 2026 roster as utility infielders, given the amount of infield depth that Milwaukee has in the minor leagues, it was difficult to see how either of them would impact the big-league team in 2027 and beyond. Moving on from them now, rather than waiting until the Brewers needed to make room for names like Cooper Pratt and Jesús Made, was a wise move.

Kyle Harrison

As for the Brewers' return, the headliner is absolutely former top-ranked San Francisco Giants prospect Kyle Harrison. Harrison, who also climbed to the Top 25 of MLB Pipeline’s MLB prospects rankings, was traded to Boston in the Rafael Devers blockbuster last season, but after just two starts with the Red Sox, he's now joining his third MLB organization in the last eight months.

There's a reason Harrison was once a top-ranked prospect; he's a left-handed starter who can run it up to 97 mph on his fastball without sacrificing much command. Paired with a decent slurve, Harrison produced a 30.5% whiff rate in his limited appearances during the 2025 season. With the ability to throw a cutter and a changeup that was deemed a "plus offering" by MLB Pipeline, Harrison has the pitch mix to continue being an effective starter at the big-league level.

As previously mentioned, adding a former Top 100 pitching prospect who still has five years of team control is a rarity in today's game. Teams understandably value their pitching prospects very highly, but the Red Sox had a surplus of them, which is why they were willing to part with someone with as much upside as Harrison. Though not a guarantee to immediately slide into the Brewers' starting rotation, fans should be very excited about the addition of Harrison to Milwaukee's pitching staff.

Shane Drohan

Drohan is the overlooked aspect of this trade, but he shouldn't be. The 27-year-old left-handed starter, who was Boston's No. 30-ranked prospect before the trade, is coming off of his best run of starts as a professional. The southpaw posted a 2.27 ERA in 11 starts with Boston's Triple-A affiliate last season, and the performance was no fluke, seeing as there were measurable improvements to Drohan's arsenal.

According to MLB Pipeline, Drohan found another tick with his fastball last year, which can now run up to 96 mph, and the movement on his slider was much improved. His command, which had previously been holding him back, improved considerably -- another reason for the better results last season.

Drohan is 27 years old and did experience some forearm inflammation last year, but Arnold offered reassurance that there are no lingering effects from the injury, saying "nothing from our end in terms of concerns there. He finished the season really strong...finished with an uptick in velocity and his stuff across the board." Though he's likely to start the season in Triple-A, don't overlook Drohan and his inclusion in this deal.

David Hamilton

The Brewers selected Hamilton in the 8th round of the 2019 MLB Draft and traded him to Boston in the deal that brought Hunter Renfroe to Milwaukee. Now, five years later, he's back in the Brewers' organization and likely to impact the big-league roster this upcoming year.

As previously mentioned, Hamilton can be thought of as canceling out Monasterio's inclusion in this trade, but there are some advantages to the former's profile. Hamilton, for one, is faster than Mona on the basepaths, and he's a better defender as well. Additionally, Hamilton is a left-handed batter, which is an asset given the fact that Joey Ortiz and Jett Williams, two players who are likely to see playing time on the left side of the infield, are right-handed.

Hamilton certainly doesn't offer much value at the plate, but he's lightning quick and doesn't chase too much, which definitely fits the Brewers' offensive mold. For a utility infielder, Hamilton is a great addition to the Brewers' roster, especially with four years of team control and a minor league option remaining. On Hamilton, Arnold said he "plays the way we love to play, very exciting, athletic, good defensive player. Along with the infield depth that we have in the system, [the trade] made a lot of sense for the Brewers."

That last note from Arnold is key; the Brewers have a ton of infield talent in the farm system that is starting to knock on the door of the big leagues. Once those guys like Pratt, Made, and Luis Peña are ready, finding a spot for Durbin, Monasterio, or Seigler was going to be difficult. Therefore, the Brewers turned a position of strength into very valuable, controllable left-handed pitching. It may seem like they gave up a lot to get it, but let's just wait and see how this one plays out.