Skip to content 
But Harrison’s numbers quickly declined, and a brutal end to the season — after a stint on the injured list with a forearm problem — left him with a 4.20 ERA in 115 2/3 innings when all was said and done. Although he made the roster for every round of the season, he did not appear once in October as the Brewers went on to win their first World Series championship.
Given his sudden ineffectiveness, it’s fair to ask what kind of prize the Brewers will get for Harrison in 2027: someone who looks like an ace at the top of Milwaukee’s rotation alongside Misiorowski and Logan Henderson, or someone moved to the bullpen late in the year amid ongoing struggles?
Here’s a look at Harrison’s ups and downs for 2026 and what the Brewers can expect from him next season.
Harrison earned a spot in the Brewers’ Opening Day rotation and ran with it, favoring hitters through the first two months of the season and into early June. In his first 11 starts, he had a 1.57 ERA with 16 walks and 73 strikeouts in 57 1/3 innings, second in MLB in strikeouts (min. 50 strikeouts) and third in ERA in nine innings.
Harrison, who split time between starts and relief in the big leagues with the Giants and Red Sox in 2025, didn’t go deep into games: He made one start longer than six innings and averaged just 5.21 innings per outing. But he was fantastic in every inning, striking out in double figures in three of those 11 starts and striking out batters with a four-pitch arsenal led by a fastball with one of the highest usage rates in the big leagues.
Harrison, MLB Pipeline’s No. 20 overall prospect when he debuted in San Francisco in August 2023, had a 4.39 ERA in the big leagues through 2026. His early success with the Brewers confirmed his breakout and cemented him as a top-of-the-rotation arm (later in Miwerson and Hewerson) given Brandon Woodruff’s lingering shoulder problem.
But in his 12th start of the season, on June 8 against the Athletics — albeit in Las Vegas Ballpark’s true home turf — Harrison was tagged for eight runs in just 2 1/3 innings, raising his ERA by more than a full run.
He followed the hitting slump with three strong starts, but after allowing six earned runs in 6 2/3 frames in two games in early July, Harrison landed on the 15-day IL with left arm strain. He did not return until August 5, and when he did, his struggles continued.
Although Harrison’s first start back from IL was excellent — he allowed just one hit over five scoreless innings, striking out 10 — he soon fell out of Milwaukee’s starting rotation. Four of his final five outings of the season came out of the bullpen, and one was a start of just 1 2/3 innings. In August and September, Harrison had a 7.31 ERA in 32 innings of work.
So what happened? That’s the question, and Harrison’s arm injury is at least part of the answer. His average fastball velocity dropped from 95.0 before the IL contest to just 93.7 mph in August and 95.2 mph in September. Need a hint that Harrison is physically hindered? After returning, the left’s average arm angle dropped to 31.9 degrees, compared to 33.4 degrees previously. Such a decline is often a sign that a pitcher is going through an injury.
While the wrist issue affected Harrison, the movement on his fastball was a concern before he was placed on the IL. Harrison averaged 15.1 inches of vertical break, AKA visible “rise” in his fastball, in his first 11 starts, and only 14.4 inches of IVB after that. Harrison struggled to get bats to miss as the whiff dropped from 31.6% to 23.0% in his four home runs.
“The Heat haven’t been as poppy,” Harrison told MLB.com in September. “I feel good, but I’ve got to get this thing together.”
It wasn’t just his fastball: Harrison was hit hard in general for most of 2026, hampering his excellent start.
Harrison’s hitting stats through June 2 (11 starts)
5.1% barrel rate
28.5% hard hitting rate
average speed 87.6 mph. output speed is allowed
Harrison’s hitting stats since June 8 (17 games, 13 starts)
10.4% barrel rate
46.4% hard hitting rate
89.8 mph avg. output speed is allowed
Those endpoints are arbitrary, of course, but it’s clear enough to see Harrison start to struggle for the first time in 2026 — more than a month before arm soreness sidelined him.
Regardless of the results, one concern for the Brewers is Harrison’s inability to go deep into games, especially this late in the year. The last time he pitched more than five innings was June 20, and he’s pitched just 3.5 innings per appearance since that point.
The Brewers are certainly fortunate that Harrison’s wrist soreness — often an indicator of a more serious injury in pitchers — was mild, and they should be glad to know that the left-hander is feeling good physically at the end of the year.
In addition, Harrison’s struggles were exacerbated by some bad hitting-ball luck: His .333 WOBA as of June 8 was well below his expected .400 WOBA. Although somewhat unlucky before that point (.260 wOBA, .278 xwOBA), Harrison finished 2026 with an expected ERA of 4.01, compared to an actual mark of 4.20.
Interestingly, Harrison’s results in 2026 fell in line with his previous performance, although there was definitely a bit more variance in his fourth big league season. Both he and the Brewers will hope for more consistency from the talented left-hander.
If that happens, and Harrison performs as regularly as he has in early 2026, watch out: The Brewers’ 1-2 punch at the top of their rotation might just be a 1-2-3 trifecta.