The Red Sox trade package to acquire starting pitcher Sonny Gray on Tuesday included them sending a top pitching prospect to the Cardinals.

Boston traded lefty Brandon Clarke, who MLB Pipeline had ranked Boston’s No. 5 prospect, to St. Louis. The Sox also parted with 25-year-old righty Richard Fitts, who missed the final 30 games of 2025 on the 15-day injured list with right arm neuritis.

The 22-year-old Clarke posted a 4.03 ERA in 14 starts for Low-A Salem and High-A Greenville in 2025. Boston drafted him in the fifth round (148th overall) in 2024 out of State College of Florida, Manatee–Sarasota and gave him a $400,000 signing bonus.

MLB Pipeline grades Clarke’s fastball 60 (above average) and his slider 70 (well/well above average) on its 20-80 grading scale.

Baseball America wrote in late July that Clarke “had more helium than any prospect to start 2025” and “there are very few lefthanders that sit in the upper 90s after being drafted, and even fewer that feature a plus slider.” Clarke went from an unranked Red Sox prospect entering 2025 to No. 81 on BA’s Top 100 list by midseason.

But some of the top-prospect hype fizzled out when he posted a 7.71 ERA in his final seven starts compared to a 1.88 ERA in his first seven starts. He’s no longer ranked on Baseball America’s Top 100 list. He also didn’t appear on BA’s top 10 Red Sox prospect list released earlier this week.

He dealt with a blister issue that limited him to just 38 innings total and could have affected his late-season struggles.

The lefty, who underwent Tommy John surgery in college, has struggled with command. While he struck out 60 batters in his 38 innings last year, he also issued 27 walks.

He grew up a Red Sox fan and roomed with David Ortiz’s son, D’Angelo Ortiz, during spring training 2025. He has a six-pitch mix with a four-seam fastball, two-seam fastball, sweeper (slider), curveball, cutter and changeup.

MLB Pipeline recently named him as a 2026 breakout prospect candidate and wrote, “Scouts have been dreaming on Clarke’s potential since he was touching 97 mph in high school, and he’s added another three ticks since. The 22-year-old unleashes it from a three-quarters release point, and his long arm action, high leg kick and elite extension add a bit of deception. The pitch doesn’t get as many whiffs as you might expect, given the velocity, but the downhill plane on the pitch has enabled him to rack up massive ground ball numbers.”