Milan: Cristiano Ronaldo's return to fitness could be vital to Juventus's bid to end their Champions League drought going back 23 years as they head to Ajax with uncertainty over whether their superstar will play or not.

Ronaldo hasn't played for the Serie A leaders since scoring a hat-trick that saw Juve come back from a 0-2 first-leg deficit to knock out Atletico Madrid last month. He was rested in the subsequent 2-0 league defeat at Genoa and then picked up a thigh injury on international duty with Portugal two weeks ago. But coach Massimiliano Allegri remains confident Ronaldo, 34, will be ready for Wednesday's game in Amsterdam.