The defender had to be withdrawn at the end of the first half of extra time.
Arteta said after the game: "I don't know [how bad it is]. He said to me 'I cannot play anymore'. I'm not sure if it was a cramp or a muscle injury.
"I am sure there will be a few of those [types of injuries] because players were exhausted, they played four times in 11 days and it was physically a very demanding game."