The Red Sox announced Sunday morning they’ve placed right-hander Richard Fitts on the 15-day injured list with a right pectoral strain.

To fill his spot, the club also selected right-hander Michael Fulmer to the active roster.

Fitts left Saturday’s game against the White Sox in the bottom of the sixth inning after feeling tightness in his shoulder area. The rookie right-hander is expected to undergo an MRI in Boston on Monday, at which point the club hopes to have a better idea of the injury’s severity.

Prior to the injury Fitts had thrown five-plus scoreless innings in the eventual 3-2 loss, and through seven career starts dating back to last September the 25-year-old has posted a 2.39 ERA in 37.2 innings.

Fulmer hasn’t pitched in the majors since 2023 due to UCL revision surgery, but prior to that had appeared in seven MLB seasons. The 31-year-old won the 2016 American League Rookie of the Year award and was named an All-Star in 2017 while pitching for the Detroit Tigers, and more recently he posted a 4.42 ERA in 58 appearances as a reliever with the Chicago Cubs during his last healthy season in 2023.

While Fulmer has been stretched out and could start for the Red Sox in a pinch, the club may be able to get by until Brayan Bello is ready to return. Fitts’ next scheduled start day would have been Thursday, when the club has an off day, so the Red Sox could skip his turn in the rotation and activate Bello the following Tuesday, April 22, against the Seattle Mariners — presuming Bello’s last rehab start next Wednesday goes smoothly.