Lazio captain Tommaso Rocchi will be sidelined for at least three weeks with a thigh injury.
The Italian striker sustained the injury during Sunday's 3-2 defeat at Genoa.
"Tommaso Rocchi underwent an MRI that revealed a second degree lesion in his left thigh," read a statement from Lazio.
The 34-year-old will miss his team's next three Serie A games as well as the UEFA Europa League last 32 tie against Atletico Madrid.
Rocchi, who has scored eight goals in 18 appearances for Lazio so far, could recover in time for the derby against Roma on 4 March.