Arsene Wenger revealed he nearly rested Alexis Sanchez and admits he does not know how long the Chile international will be sidelined for after he picked up an injury against Norwich City.
Sanchez was forced off after an hour of Sunday's 1-1 Premier League draw at Carrow Road after pulling up with a hamstring problem when closing down defender Ryan Bennett.
Arsenal had earlier lost Laurent Koscielny to a first-half knock and Santi Cazorla required treatment after accidentally catching Sebastian Bassong with a kick.
"We lost Alexis Sanchez, I do not know how long he will be out, but it is a big blow," Wenger told Sky Sports. "Cazorla finished on one leg, he has a knee problem. Koscielny we will have to assess tomorrow, he has a hip problem.
"I would have rested Sanchez, but he said to me before the game he was fine to play. He was an important loss, he pushes defenders back and always is incisive with his dribbling."
Wenger felt his side lacked their usual sharpness as the visitors failed to get the three points which would have taken them level with league leaders Manchester City.
"The quality of the performance was below what we can do offensively," he said.
"In the second half Norwich had good chances and we were playing against a team that is physically clever, they defender deep to catch us on the counter-attack and we were a bit jaded, not as sharp as usual."
Arsenal are now three without a win in the top flight, having been held at home by Tottenham before falling to defeat at West Brom last time out.
