The Germany international was replaced at half time in the 3-2 Serie A loss to Genoa on Sunday and is now poised for a spell on the sidelines.
A statement on the club website read: "This morning Miroslav Klose was visited by Professor Muller Wohlfahrt in Germany, his own doctor, who diagnosed a severe lesion of the external collateral ligament in his right knee.
"The player will return to Italy either tomorrow or on Wednesday and start the protocol prescribed by the German specialist. The estimated recovery time is about seven to eight weeks."
Klose has scored 10 league goals for Lazio this season.