Cristiano Ronaldo is to undergo tests on an ankle injury, Juventus have confirmed.

The Portugal star took a knock during the 1-0 Serie A victory over Bologna last Sunday, in which he played the full 90 minutes.

Ronaldo trained separately from his team-mates on Wednesday and the club say he will need medical checks on the problem.

Juve confirmed via their official website that "check-ups have been scheduled for today and tomorrow [Thursday] following a knock to his left ankle during the game against Bologna".

Ronaldo has scored 19 goals in 24 starts in Italy's top flight since he moved from Real Madrid last July in a €112million deal.

The Serie A leaders face Napoli at the San Paolo on Sunday knowing that a win will move them 16 points clear at the top of the table.

They then face Udinese at home on March 8, before the second leg of the Champions League last-16 tie with Atletico Madrid four days later.