Red Sox promote local pitching prospect Shea Sprague to High-A Greenville

The Red Sox have promoted pitching prospect Shea Sprague from Low-A Salem to High-A Greenville, according to the club’s MiLB.com transactions log.

Sprague, 22, was selected by the Red Sox in the 13th round (387th overall) of last summer’s draft as a junior coming out of North Carolina. The Hanover, Mass. native — who graduated from Boston College High School in 2021 and attended Elon University for the first two years of his collegiate career — signed with his hometown team for a slightly-over-slot $155,000 but did not make his professional debut until last month.

Sprague struggled out of the gate to begin the 2025 season, surrendering 12 runs (nine earned) in his first two outings (5 2/3 innings) for Salem. The left-hander seemingly flipped a switch on April 23, however, only allowing four earned runs over his next five appearances (24 2/3 innings) while holding opposing hitters to a .195 batting average leading up to Friday’s promotion.

“I think I just settled in, started going after guys,” Sprague said of his early-season turnaround in a recent conversation with MassLive.com’s Christopher Smith. “Kind of went through a similar preseason, early-season struggle last year at UNC, trying to be too cute. But I just started going at guys and trusting my stuff. So that’s probably been the biggest change. Nothing major.”

Overall, Sprague posted a 3.86 ERA (2.45 FIP) with 35 strikeouts to nine walks in seven outings (two starts) spanning 30 1/3 innings for Boston’s Carolina League affiliate. In a case of reverse splits, he proved to be more effective against right-handed hitters (.247 opponents’ batting average) than left-handed hitters (.304 opponents’ batting average), which happened to him in college as well.

Among the 45 pitchers in the Carolina League who had thrown at least 30 innings coming into play on Friday, Sprague ranked second in FIP, fourth in xFIP (3.01), fifth in swinging-strike rate (14.8 percent), eighth in walk rate (6.9 percent), ninth in walks per nine innings (2.67), 10th in strikeouts per nine innings (10.38), 12th in strikeout rate (26.7 percent), 20th in groundball rate (43.4 percent), and 21st in ERA, per FanGraphs.

Standing at 6-foot-3 and 215 pounds, Sprague throws from a three-quarters arm slot and operates with a four-pitch mix that consists of an 89-92 mph fastball with sink, a low-80s whiff-inducing changeup, a 79-81 mph gyro slider, and a developing sweeper. The projectable southpaw told Smith that one of his goals is to continue adding velocity to his heater and get in the 92-94 mph or 93-95 mph range within the next year.

“The Red Sox stress to us just the importance of velocity,” said Sprague, who is doing drills with weighted plyo balls as part of his side work. “Obviously, I think a lot of velocity comes from physical development, so just getting bigger, stronger, faster. And just throwing more intent more often. Workload and all that stuff. So they have it down to a science, and they’re good about it. It just comes with time, keep working hard, and keep throwing hard.”

Sprague, who just turned 22 in January, is not currently ranked among Boston’s top pitching prospects by publications such as Baseball America, MLB Pipeline, or SoxProspects.com. He is, however, slated to join a pitching staff in Greenville that includes the likes of fellow southpaws Payton Tolle, Eduardo Rivera, Noah Dean, Brandon Clarke, Michael Sansone, and Zach Fogell.