10 Crazy Things Cristiano Ronaldo Has Done
The Portuguese was dismissed for an incident with Valencia defender Jeison Murillo in which he appeared to pull his hair.
And UEFA could extend the ban to two or three matches if they feel it was violent conduct from Ronaldo.
That could mean the 33-year-old misses a dream return to Manchester United and Old Trafford.
Ronaldo’s Juventus team-mate Miralem Pjanic netted twice in the 2-0 win over Valencia from the penalty spot.