Bassitt was removed from Wednesday's game against Boston due to lower-back tightness, Jacob Calvin Meyer of The Baltimore Sun reports.
Bassitt made it through just three innings Wednesday, allowing three earned runs on six hits and two walks while striking out one batter before his back forced him out of the game. The team hasn't provided any information regarding the severity of the right-hander's injury, so it's unclear whether he'll be ready for his next start -- tentatively scheduled for Monday against Seattle.