The England international midfielder has missed the entire season through injury, after rupturing ankle ligaments in a pre-season friendly.
Wilshere looked to be on the verge of return at the turn of the year, but a fresh injury has kept him out of action, with no date set for his return.
“It is difficult to set a deadline on Jack. We go week by week with him. But his last scan was very good so we don’t have worry anymore,” Wenger told the club’s official website.
“It is about progress and fitness, however I can’t set a date.”
Wenger has received a boost ahead of Wednesday night’s clash with Everton at Goodison Park, as Thomas Vermaelen and Andre Santos are fit to play, with Abou Diaby stepping out for the reserves.
“Vermaelen had a kick on his calf and after the game he had a big pain but he is alright.
“Santos is fit enough to start but he was like that for the Newcastle game.
“Diaby is back but he is with the reserves at Liverpool. He will play for an hour,” the French coach concluded.
By Gareth McKnight