Saracens flanker Michael Rhodes had a citing complaint dismissed by an independent disciplinary committee on Tuesday.
Rhodes was cited for headbutting Leinster centre Robbie Henshaw during his side's European Champions Cup win on Saturday.
The South African could have faced a penalty ranging from six weeks to a maximum 104 weeks if the citing had been upheld.
But a panel dismissed the charge and he is able to play against French side Racing 92 in Saturday's European Champions Cup semi-final, subject to a potential European Club Rugby appeal.
"The Committee decided that Rhodes had committed an act of foul play, however, it was not proven to the required standard that contact had been made to Henshaw's head," a statement read.
"The Committee concluded that the act of foul play did not warrant a red card and the citing complaint was therefore dismissed."
Rhodes, 32, previously represented the Sharks, Lions and Stormers in his country of birth.