Lecce's survival hopes have been dealt a blow after Andrea Bertolacci was ruled out for three weeks.
The 20-year-old playmaker, who is on loan from Roma, has been a revelation this season.
He had to be replaced after 50 minutes against Sampdoria at the weekend.
Bertolacci complained of a muscle injury and underwent a scan, which has since revealed a muscle tear.
He had been called up to represent the Italy Under-21s in last night's friendly with Russia.
Lecce's medical staff expects Bertolacci to return for the match against Napoli on May 8.