Wales centre Gavin Henson has been axed from the Ospreys' opening European Cup games against Leicester and Perpignan in what the Welsh outfit described as a "rugby-related disciplinary decision".
The shock move came less than a week after Henson made his first start of the season, returning from an ankle injury during Ospreys' narrow Anglo-Welsh Cup victory over Harlequins.
Reports suggested a disagreement over his training schedule were at the origin of Henson's exclusion, which has resulted in Andrew Bishop being drafted into the side that will travel to Leicester on Sunday.
And with regular outside centre Sonny Parker sidelined by a chest muscle injury, wing Tommy Bowe will be moved into midfield.
Henson said: "Having received feedback from team management earlier in the week as part of a review of the Ospreys' last home game, I reacted poorly and additionally took unauthorised leave to consider the matters raised.
"Having signed up to the Ospreys' code of conduct introduced earlier this year, I was part of a disciplinary decision from the Ospreys leadership group which consists of senior players and rugby management.
"I fully accept this decision and entirely support the penalty imposed, and very much look forward to rejoining my team-mates on the field."
Henson's lack of match practice is likely to concern Wales boss Warren Gatland with less than two weeks to go until he names his squad for November Tests against South Africa, Canada, New Zealand and Australia.
Ospreys coach Sean Holley said his squad were determined to make an impact on this season's tournament.
"Like all professional rugby outfits, we have had injuries to contend with, but the squad is in very good shape going into this competition and we are ready for the challenge," Holley said.
"The players want to get off to a good start in Leicester, and it has been a very difficult selection process this week with so many players in numerous positions challenging for a starting place. A lot is at stake, as there always is in the first pool match in this competition, and we will need to be both focused and determined against a quality team if we are to achieve our aim."