Gavin Henson's return to action was again put on hold as he failed a late fitness test ahead of the Ospreys' 43-28 Powergen Cup victory at Bristol.
Gavin Henson was hoping to return for the first time after a groin injury
The Wales international, who has not played since the second Lions Test in New Zealand in July, suffered a back strain in training last week.
However, he is pencilled in for the Ospreys' Heineken Cup tie at Leicester next Sunday.
"Gavin was devastated not to play this game," said Ospreys' coach Lyn Jones.
"He trained on Saturday morning and looked very good but his back stiffened afterwards and he couldn't move freely prior to coming to Bristol.
"If he is to have any chance of playing at Leicester, he would need to train fairly injury-free and it wasn't worth risking him and possibly aggravating the injury for this match."
Henson underwent groin surgery after the Lions tour to New Zealand.