AC Milan's Ronaldinho has suffered a slight thigh strain, the club said in a statement, making the Brazilian a doubt for Monday's trip to fourth-placed Napoli.
The game is the first to be played on a Monday as part of moves to better market Serie A. Other measures include a Sunday lunchtime kick-off, television cameras in the dressing room and halftime interviews.
Reports say Milan coach Massimiliano Allegri, whose side are second, is planning changes irrespective of Ronaldinho's injury following Tuesday's 2-0 loss at Real Madrid in the Champions League.
Juventus forward Alessandro Del Piero will break Giampiero Boniperti's record of 178 Serie A goals for the club if he scores in Sunday's match at struggling Bologna.
The 35-year-old played all of Thursday's 1-1 Europa League draw at Salzburg, where in-form winger Milos Krasic again came to the rescue.
Full-back Zdenek Grygera suffered a knee injury in Austria and reports say he could be out for several weeks.
Midfielder Dejan Stankovic looks set to miss third-placed Inter Milan's home game with Sampdoria on Sunday after coming off in Wednesday's 4-3 Champions League win over Tottenham with a calf injury, which could keep him out for around two weeks.
Fiorentina director Andrea Della Valle has backed coach Sinisa Mihajlovic despite the injury-hit Florence club slumping to the bottom of the table ahead of Saturday's visit of Bari.
"His position is absolutely not under discussion. He is not the problem," Della Valle told reporters.
Striker Adrian Mutu returns from a long drugs ban at the end of the month.
League leaders Lazio have been given the go ahead from authorities to continue flying their eagle mascot Olimpia around the Stadio Olimpico before Sunday's game with Cagliari.
Animal rights activists had complained but the club announced the bird would be staying as 3,000 fans, still stunned by the team's form this term, turned up for a training ground friendly on Thursday.
