Cardiff Blues coach Dai Young has called on the Welsh regions to honour promises to rest Test players.
The four teams originally agreed to allow a 10-week rest and pre-season for players on Wales' summer tour.
But that would rule them out of the first three Celtic League games, with the Scarlets and Ospreys asking for players to be assessed individually.
"We all agreed to this, but if we're the only ones to adhere to that we're going to have a rethink," Young said.
"We were asked by (Wales fitness coach) Andrew Hore and the Welsh Rugby Union to support an initiative that these players needed a four-week break and a six-to-eight weeks minimum pre-season training.
"It's something we all need to buy into, but if we're not all doing that there's no way I could totally disadvantage my region by being the only one to stick to the agreement."
Hore wants Wales to follow Ireland's approach, whose international players will miss the first three weeks of the Celtic League.
But the Irish Rugby Football Union does not use finishing positions in the Celtic League as the sole decider for Heineken Cup qualification.
With the lowest placed of the four Welsh regions dropping into the lower tier Parker Pen European competition next season, there is greater pressure on Welsh coaches to field their strongest side.
But the fear is that without an enforced rest the year-round wear and tear on top players - evident last season following the World Cup - will continue to tell.
"It was done not only for the benefit of Wales - I think it's been lost a little bit that it's for the betterment of the individual players," Young added.
"I totally understand that it puts huge strains on the regions - and I'm not having a go at anyone - but we all need to do the same thing.
"Regional rugby (in Wales) is still in its infancy and little things like this will always crop up.
"I think we can expect something like this to appear every season for the next two or three years."