The French striker has been out since injuring his ankle in the second game of the season at Everton.
Wenger paid Manchester United £16m for Danny Welbeck following the injury to Giroud, as he faced up to a striking crisis at Emirates Stadium.
And the Gunners boss insists Giroud will have a battle on his hands to win his place back in his first-team.
"There are no indisputable players at a big club," Wenger told BEin sports. "There are only players that are in form who play.
"Giroud is a player who is considered as a potential starting XI player, but he is like Welbeck, he is like Sanchez. They need to be in form."
Giroud is nearing a return to action after returning to training prior to the international break.
