CLEVELAND (AP) — Boston’s pitching staff took another big hit Wednesday as the Red Sox placed starter Brayan Bello on the injury list with upper back tightness.

Bello’s injury means the Red Sox are missing three of five starters, and that doesn’t include Lucas Giolito, the team’s biggest offseason acquisition, who is out for the season with a torn elbow ligament.

Bello felt tightness in his back following his most recent start, and the Red Sox decided to be cautious and put him on the IL. Bello recently signed a six-year, $55 million contract extension.

Manager Alex Cora doesn’t believe the 24-year-old Bello will miss significant time.

“He’ll be OK. This is more of taking care of him,” Cora said before Wednesday’s game. “Hopefully he’ll be back when he’s supposed to come back. He’s very important for this organization, not only now but in the future and if we take care of this and he’ll be fine.”