CHICAGO -- Boston Red Sox right fielder Tyler O'Neill could be going back on the injured list after his ailing right knee flared up again Friday night.
O'Neill was just activated from the 10-day injured list Wednesday after being sidelined by right knee inflammation.
"I don't know what the next steps are going to look like," O'Neill said after Boston's 7-2 loss to the Chicago White Sox. "But I just want to get it cleaned up as soon as possible. It's not fun playing in pain."
O'Neill said he tweaked the knee when he hauled in Paul DeJong's fly ball in the second inning. After Lenyn Sosa popped up to catcher for Chicago's first out of the third, O'Neill walked off the field with manager Alex Cora and a trainer.
"It's just really frustrating with how I was feeling," O'Neill said. "I was feeling really good earlier in the day."
Rob Refsnyder, who moved from left to right field as part of a flurry of moves after O'Neill departed, then made a terrific diving catch on Corey Julks' sinking flyball for the second out of the inning.
O'Neill was acquired by Boston in a December trade with St. Louis. He went on the IL with the knee issue on May 29.
O'Neill, who turns 29 on June 22, is batting .250 with 11 homers and 18 RBIs in 44 games.
"We got to be very careful," Cora said. "Playing short is hard, but let's see where we're at tonight and we'll decide what we do tomorrow."