The players picked up their respective problems during the Rossoneri's 1-0 away defeat to Juventus in Serie A on Sunday.
"AC Milan would like to communicate that Massimo Ambrosini sprained his right ankle during the match against Juventus and has suffered some ligament damage," reads a statement on the club's official website.
"Christian Abbiati, meanwhile, has strained his right calf. Both will have a better idea of how long their recovery time will be further into the week."
Milan are currently third in Serie A with 59 points from 33 matches.