Montolivo has not featured for the San Siro side since its 2-2 Serie A draw against Torino on Sept. 14, but the midfielder could make Tuesday's Champions League clash with Ajax after resuming regular training at the weekend.
El Shaarawy, meanwhile, has been out of action ever since his brief substitute cameo against Cagliari at the start of the month, but is also raring to go again after returning to the training pitch.
However, Allegri has stressed that he may need to use the returning players sparingly ahead of the vital clash with champion Juventus on Sunday.
"I'll have to manage them as best I can because we’ll be up against Juventus after the game versus Ajax," Allegri told reporters.
Milan got its Champions League campaign under way with a win 2-0 win over Celtic.