Juventus full-back Patrice Evra could miss key fixtures against Napoli and Lyon after picking up an injury in Wednesday's 4-1 win over Sampdoria at the Juventus Stadium.
Evra will undergo tests on Thursday after limping off with a calf problem.
Alex Sandro -- who has been preferred to the Frenchman in eight of Juve's 10 Serie A fixtures this season -- is set to take his place against Napoli and Lyon.
But Juventus coach Massimiliano Allegri defended his training methods, criticised last season after a succession of muscle injuries, and said they were not to blame for Evra's injury.
"We've only had four muscular injuries this season, and then there have been Kwadwo Asamoah and Marko Pjaca's injuries which are not of a muscular nature, so that pushes the average up a bit," Allegri he said.
"It's nothing compared to last season, when it seemed like we were a walking graveyard."
Allegri welcomed back Claudio Marchisio after six months on the sidelines on Wednesday and told the club's official website: "I'm pleased -- it was a great comeback from him.
"His return is important but now I will have to manage him the best I can because, after so many months out, you often tend to play a good first game back."