Arsenal manager Arsene Wenger will assess Alexis Sanchez ahead of the clash with Manchester United on Saturday evening.
The Chilean forward is already on 12 goals in his debut season with the Gunners, but having been drained by a gruelling travel schedule back from international duty in South America following friendlies against Uruguay and Venezuela his fitness will be monitored.
"It is a concern, of course. He looked a bit jaded just before he went and I will have to check him before Saturday," said Wenger, who has not spoken directly with the Chilean federation about its use of the player.
Sanchez played 85 minutes in Chile's 5-0 win vs. Venezuela and the full 90 minutes in his country's 2-1 loss to Uruguay. Arsenal face Manchester United on the weekend.
"Don't ask him the question (about being fit to play) because he will say he is perfect," the Frenchman added.
Both Arsenal and United have struggled for consistency this season, sitting sixth and seventh in the Premier League table. Wenger, though, insists Dutch boss Louis van Gaal can help turn United's form around.
"We are of the same generation. He is passionate, competent, intelligent and has personality. Without those qualities you don't last for such a long time like he has in international football. So he has the qualities to do it," said Wenger, now the longest-serving manager in the top flight following Sir Alex Ferguson's retirement.
"It is early stages (of the season). They are still candidates to finish in the top four, and I will tell you more on Saturday afternoon."