De Kock Steenkamp will see specialists this week to discover the extent of an Achilles injury sustained in training for the Ospreys.
Two tries from Tommy Seymour were the highlight as Glasgow Warriors returned to the top of the PRO12 table with a 40-23 victory over Treviso in Italy.
Ospreys made it five wins from five games so far in the Pro12, as they picked up a less than comfortable victory over second-bottom Zebre.
Sean O'Brien will miss Ireland's November internationals and possibly the Six Nations as well, after being ruled out for up to six months.
PREVIEW: Glasgow Warriors coach Gregor Townsend urged his players to ensure the defensive frailties that almost cost them against Connacht.
Ulster tighthead prop, Declan Fitzpatrick has been given a one week suspension following the red card he received in the match against Zebre on Saturday.
Cardiff Blues have captured the signature of Pumas back Lucas Amorosino, the former Leicester man will bolster the back division.
Two quickfire scores from Hallam Amos finally kick-started Newport Gwent Dragons season with a 33-15 win over Treviso
Dan Biggar fired Ospreys back to the top of the Pro12 table with a composed kicking performance in a narrow 19-14 victory over Munster.