Initial imaging showed damage in the right elbow of Boston Red Sox starter Lucas Giolito that could cause him to miss the 2024 season, league sources told ESPN.

Giolito, who was expected to be the Red Sox's Opening Day starter, has a partially torn ulnar collateral ligament and flexor strain that could require surgery that would likely keep him out for the entirety of 2024, according to sources.

Giolito, 29, was one of just three free agent signings by the Red Sox over the winter, alongside reliever Liam Hendriks -- who is expected to miss most, if not all, of 2024 after undergoing Tommy John surgery -- and right-hander Cooper Criswell. While Red Sox chairman Tom Werner had suggested at the outset of the winter that the team would take a "full throttle" approach to free agency, Giolito's two-year, $38.5 million contract represented more than three-quarters of their $49.5 million outlay, which ranks 13th in Major League Baseball.

Coming off their third last-place finish in four seasons, the Red Sox enter 2024 with a rotation that's now in flux. Boston traded left-hander Chris Sale in the offseason and replaced him with Giolito, a veteran whose ability to consistently provide innings was seen as a necessity for a rotation without other established starters.

Giolito underwent Tommy John surgery in 2012, about two months after the Washington Nationals selected him with the 16th pick in the draft. It's unclear whether he would need the full reconstruction Tommy John surgery provides or whether the partial tear would allow him to undergo an internal brace procedure that has a shorter recovery timeline. Regardless, a combined repair of the UCL and the flexor -- a mass of muscles in the forearm that serves to dampen the stress on the elbow ligament -- would necessitate a recovery of well over six months. Giolito could try to rehabilitate the injury, but if that approach fails, it could jeopardize his 2025 season as well.

How Boston pivots, following a winter that caused consternation among its fan base, will be indicative of how invested ownership is in this year's team.

Boston's monthslong dalliance with free agent left-hander Jordan Montgomery has remained at a standstill, as Montgomery seeks a long-term deal the Red Sox have not been willing to give. National League Cy Young winner Blake Snell remains a free agent as well.

Should the Red Sox prefer not to dabble in the $20 million-a-year range, the top starter options include right-handers Michael Lorenzen and Mike Clevinger. Other free agent starters include right-handers Zack Greinke, Noah Syndergaard, Johnny Cueto, Jake Odorizzi and Domingo German, and left-handers Eric Lauer and Rich Hill.

Giolito started 33 games among three teams last season, posting a 4.88 ERA and striking out 204 in 184 innings. In his eight-year career, he is 59-52 with a 4.43 ERA and 1,077 strikeouts against 385 walks in 1,013 innings.