The Chilean international picked up a knock a fortnight ago against Manchester United, only to fly across the world to play in two games for his country - scoring in both.
He continued this form with a goal against Watford at the weekend but Arsene Wenger believes caution is now needed.
He said: "You could see he was a bit jaded physically tonight and he still pushes himself so much but he finished exhausted. The two games with Chile, plus travelling, plus Watford, plus tonight, it is too much."
Arsenal have an important game with Everton at the weekend, and Wenger's comments don't go as far as suggesting he could be out, but they will have to treat him carefully with regard to training.
What about Aaron Ramsey?
It sounds less positive for Aaron Ramsey, who was substituted midway through the second half with the game goalless after picking up an injury.
Arsene Wenger says the Welshman has told him he will miss the weekend clash, and potentially longer, although the club are yet to put an official timeframe on his injury.
He said: "He is alright but very down because he told me that his hamstring is quite a tough one. He is out."