Wenger said: "If the situation is still like this in January we will see. We are still in November. November and December is plenty of time to win his place back.
"He is up for the challenge because he is 200% professional."
Lehmann has not played for Arsenal since August 19, when he allowed David Dunn's 25-yard-strike to slip through his hands as Blackburn earned a 1-1 draw.
Lehmann turned 38 on Saturday but Wenger said: "Jens doesn't want any presents. Jens wants to play because he thinks he is the best keeper.
"It makes it worse to put him in and out again. He has done nothing wrong. Almunia has been in the team and the team is doing well. It is as simple as that."