Midfielder Arsenal Francis Coquelin injured his hamstring in a match against Bournemouth (3-0).
Coquelin came on as a substitute in the 67th minute of the match against Bournemouth, but after 15 minutes he was forced to leave the field because of an injury.
Given that by the time Arsenal had used all three replacements, Arsen Wenger's team had to finish the match with a ten-man.
After the game, the manager of the "Gunners" said that the French midfielder has a hamstring injury.
"He has problems with the hamstring. I do not know how serious they are, but he certainly will not play next week, "Wenger said..
Thus, Coquelin will miss the match of the Europa League against Cologne and the Premier League meeting against Chelsea.