Juventus are ready to test Sir Alex Ferguson's resolve over Dimitar Berbatov.
Juve are eyeing up Berbatov, who is having an erratic season at Old Trafford.
Since scoring seven goals in his first six games, United's record £30.75million striker has not netted in his last nine appearances.
Berbatov, 29, was so bad at Aston Villa 10 days ago that Fergie dropped him completely from his squad for Saturday's win over Wigan.
His long-term prospects at Old Trafford do not look good now that Wayne Rooney is staying and Javier Hernandez already appears to have overtaken him in the strikers' pecking order.
United have yet to open contract talks with Berbatov, whose current deal expires in June 2012, and Juventus believe they can lure the Bulgarian to Turin in January.
Although Ferguson is highly unlikely to consider selling Berbatov during the next transfer window, he may be prepared to listen to offers in the summer if he decides he has had the best out of the former Tottenham star.