Milan - Juventus midfielder Andrea Pirlo is set for scans on a calf problem on Wednesday amid fears he could be ruled out for several weeks.
Pirlo pulled up before half-time in Juve's 2-1 Champions League last 16, first leg victory over Borussia Dortmund in Turin.
Coach Massimiliano Allegri confirmed Pirlo had gone "off with a calf problem" but Italian media are speculating the 35-year-old, who missed the start of the season due to injury, could be out for a month.
If confirmed, Pirlo, Italian footballer of the year for the third year running last year, could miss the key upcoming games against Roma and the return leg against Dortmund on March 18.
Juventus are top of Serie A with a nine-point lead over Roma ahead of their visit to the Stadio Olimpico on Monday.