The Red Sox announced Eovaldi has been placed on the 10-day injured list because of a loose body in his right elbow.
Elbow problems have been persistent throughout Eovaldi's career. He's already had Tommy John surgery twice, in 2007 and 2016. The Texas native had arthroscopic surgery to remove loose bodies in his elbow in March 2018 when he was playing for the Tampa Bay Rays.
Boston's injury list contains a number of players previously expected to play key roles for the club in 2019. Eovaldi joins a group that already included Dustin Pedroia, Eduardo Nunez, Brian Johnson and Brock Holt.
The Red Sox acquired Eovaldi from the Tampa Bay Rays in July, and he was instrumental in their run to the World Series in the fall. The 29-year-old threw 97 pitches in six innings of relief with one day of rest in the 18-inning Game 3 against the Los Angeles Dodgers, surrendering the walk-off home run to Max Muncy after holding the Dodgers scoreless for the rest of his time on the mound.
Boston re-signed Eovaldi to a four-year, $68 million deal in December. He's off to a slow start this season, with a 6.00 ERA, 16 strikeouts and 11 walks in 21 innings over four starts.
Through 20 games, the Red Sox are in last place in the American League East with a 7-13 record.