AC Milan's injuries mean David Beckham is likely to be in the starting lineup again for Sunday's big match at Juventus after playing well in Wednesday's 5-2 win over Genoa, the first match of his second loan stint from Los Angeles Galaxy.
Second-placed Milan, eight points behind city rivals Inter with a game in hand, will probably be without Alexandre Pato because of the thigh injury that caused him to miss the Genoa match.
The club said Trezeguet's ankle problem would sideline him for around six weeks.
Inter captain Javier Zanetti may shift from midfield to defence for Saturday's home game against bottom club Siena to cover for Cristian Chivu, who fractured his skull in Wednesday's 1-0 win at Chievo Verona.
Luca Toni will make his first start for fifth-placed AS Roma in Saturday's home game against Chievo, coach Claudio Ranieri told reporters.
The forward, on loan at the Rome club after falling out of favour at Bayern Munich, was expected to start Wednesday's 2-2 draw at Cagliari with Francesco Totti out injured but he went on only in the closing stages.
Atalanta will be in the hands of academy coach Valter Bonacina for Sunday's visit to Palermo while the second-from-bottom side look for a permanent replacement for Antonio Conte, who quit on Thursday.
