Francis Coquelin could be set for a spell on the sidelines after sustaining a hamstring problem in Arsenal's fraught 3-3 Premier League draw at Bournemouth.
Coquelin, 25, midfielder was replaced at Dean Court after just 26 minutes, and now faces a scan to determine the extent of the problem.
Olivier Giroud's header two minutes into added time salvaged a point for Arsenal, who had trailed 3-0 on the hour thanks to goals from Charlie Daniels, Callum Wilson and Ryan Fraser.
Alexis Sanchez and Lucas Perez kick-started Arsenal's comeback with Cherries captain Simon Francis sent off late on, before Giroud scrambled the draw.
"Coquelin has a hamstring [problem]," Arsenal boss Arsene Wenger said. "We have to wait 48 hours for the scan and the result. But usually when he sits down and comes off it's not so good news.
"If it's just tiredness he will try to play on but he didn't even try to play again."
Bournemouth went into the contest after enjoying an extra day's rest on Arsenal, and Wenger felt that definitely affected the tie's outcome.
"We had three or four players we had to play tonight that we had to wait until the warm-up to see if they could play," Wenger said.
"Hector Bellerin had a knock he was uncertain to play, and that's the problem with only 48 hours [between games], you have to play some players again.
"Laurent Koscielny too, and we had Gabriel [Paulista] that we didn't start in the end.
"And then I didn't start Alex Oxlade-Chamberlain because I didn't take a gamble with him, because I didn't know who we'd have to take off.
"This complicates the job a lot, but we have to shut up and cope with it.
"Look I'm ready to play tomorrow again as long as we play against an opponent who has played today as well. That is what I call fair.
"We have to play when we are told to play. But we want to play against teams in the same time of rest and preparation as we have."