Juventus manager Massimiliano Allegri remains optimistic of having Cristiano Ronaldo fit for the Champions League quarter-final against Ajax but will not rush the forward's return.
Ronaldo suffered a hamstring problem while away on international duty with Portugal.
Reports have suggested the 34-year-old aggravated the injury during his recovery with the Serie A club.
Before heading away with Portugal, Ronaldo helped the Bianconeri secure a place in the last eight of the Champions League with a stunning hat-trick to beat Atletico Madrid 3-0 in Turin and complete a remarkable turnaround.
Allegri confirmed Juve would not rush their star man back into action unless fully fit, with the runaway Serie A leaders set to play Cagliari away on Tuesday night.
"Cristiano Ronaldo is working to get back, we hope to have him ready for Ajax, but it will be difficult," Allegri said.
"The leg is much better. We still have nine days to go to the Amsterdam game and we have time to evaluate things. We must be careful in everything."
Juventus hold a 15-point lead at the top of Serie A, while tonight's opponents Cagliari sit 12th.