The Rossoneri are currently third in the league, but Fiorentina, who travel to Pescara, are two points behind and breathing down their neck.
Nigel de Jong has been on the sidelines since December and will not return to the squad until next season.
Meanwhile, relegated Siena have lost their last five games in a row and will be playing for pride at the Stadio Artemio Franchi.
Giuseppe Iachini has no injury concerns and will choose from a full complement.
Siena: Pegolo; Terzi, Terlizzi, Felipe; Vitiello, Bolzoni, Calello, Della Rocca; Grillo, Agra; Emeghara
Milan: Abbiati; De Sciglio, Zapata, Mexes, Constant; Flamini, Ambrosini, Boateng; Pazzini, Balotelli, El Shaarawy
Sports Mole says: 1-2