Ospreys will be without George Stowers for their final Heineken Cup pool games after being banned for four weeks.
Stowers has been suspended for a dangerous tackle on Dragons wing Tanderai Chavhanga in the 67th minute of the 21-20 defeat at Newport.
But his back-row colleague Jonathan Thomas has been cleared to play against Treviso and Biarritz after being cleared of a dangerous tackle.
Thomas is free to continue playing after the citing was not upheld.
After viewing Stowers' tackle on Chavhanga from various TV angles the disciplinary committee found the tackle merited a low-end entry point of two weeks in the IRB's list of recommended sanctions list.
But they increased the sanction by one week in view of the player's poor disciplinary record in the past 36 months and a further one week in line with the IRB's recent memorandum on dangerous tackling.
Stowers can resume playing on 9 February and has the right of appeal.
The Ospreys host Treviso at the Liberty Stadium on Friday night before travelling to Biarritz nine days later.