Red Sox promote relief prospect Michael Sansone to High-A Greenville

The Red Sox have promoted left-hander Michael Sansone from Low-A Salem to High-A Greenville, as was first reported by Hunter Noll of Beyond the Monster.

Sansone started the season in Salem’s bullpen after spending most of 2024 with Boston’s Carolina League affiliate. To open the 2025 campaign, the 25-year-old lefty posted a 2.75 ERA and 2.92 FIP with 22 strikeouts to just one walk in 10 relief appearances (19 2/3 innings) for the Red Sox. He converted two of his three save opportunities as opposing hitters batted .233 against him.

Among 85 Carolina League pitchers who entered play Tuesday having thrown at least 19 innings this year, Sansone ranked first in walks per nine innings (0.46) and walk rate (1.3 percent), fourth in WHIP (0.92) and xFIP (2.66), ninth in swinging-strike rate (16.1 percent), 13th in FIP, 16th in strikeout rate (29.3 percent), 19th in ERA, 26th in line-drive rate (19.2 percent), and 31st in strikeouts per nine innings (10.07), per FanGraphs.

Sansone began his professional career with the Rays organization after spending four years at Fairfield and going undrafted in July 2022. The Connecticut native made a handful of appearances in the Florida Complex League that summer and compiled a 3.49 ERA (3.10 FIP) in 15 relief outings (28 1/3 innings) for Tampa Bay’s Low-A affiliate the following season before being released in July 2023. He then signed with the Yolo High Wheelers of the independent Pioneer League last March, only to have his contract purchased by the Red Sox a few weeks later.

Sansone reported to Salem shortly thereafter and finished 2024 with a 3.11 ERA (3.25 FIP) in 20 appearances (three starts) spanning 72 1/3 innings. Altogether, the dimunitve southpaw owns a 3.14 ERA (3.16 FIP) with 127 strikeouts to just 15 walks over 120 1/3 career innings at the Low-A level dating back to April 2023, so one could say this is a well-earned promotion.

Standing at 5-foot-9 and 195 pounds, Sansone throws from a three-quarters arm slot and incorporates some deception into his delivery. Not known for his velocity, he primarily operates with a three-pitch mix that consists of an 88-90 mph fastball, an 83-84 mph slider and a 79-80 mph changeup, as noted in his SoxProspects.com scouting report.

Sansone, who turns 26 in November, is not currently ranked among Boston’s top 60 prospects by SoxProspects.com. In Greenville, he is slated to join a bullpen mix that, at present, includes fellow lefty Zach Fogell and righties Isaac Stebens, Matt McShane, Cooper Adams, Adam Smith, and Darvin Garcia.

Greenville’s series opener against Bowling Green on Tuesday was postponed due to inclement weather. It will be made up as part of a seven-inning doubleheader on Wednesday night.