Sam Warburton could go into the 2014-15 season without a team to play for because of the row between the Welsh Rugby Union and the four regions.
Wales captain Warburton, 25, is the only WRU centrally-contracted player.
Cardiff Blues, Ospreys, Scarlets and Dragons have signed a “legally-binding agreement” that stops them selecting players on a central contract.
The agreement was confirmed by a spokesperson for Regional Rugby Wales (RRW), which represents the teams.
Flanker Warburton signed a
after failing to agree a new deal with his region Cardiff Blues.
However, it was understood at the time he would continue to play for the Blues while the WRU paid his salary.
RRW re-affirming their policy not to select players on central contracts comes after talks aimed at resolving the long-running dispute between the regions and WRU over funding and player-release stalled.
The impasse led to RRW writing to the WRU offering them the opportunity to
who claim they face a combined loss of Â£6.7m if no deal can be agreed.
In extreme circumstances the regions may even be forced to offload players.
In the letter to the WRU the regions also highlighted their willingness to accept the principle of “national dual contracts” for Wales Test stars.
They wrote: “We have compromised and notwithstanding significant misgivings from a number of us have agreed to your demands for national dual contracts.”
Warburton was identified by the WRU in the autumn of 2013 as one of six players they would consider offering central contracts if they could not agree new terms with their regions.
Of the others, Alun Wyn Jones (Ospreys), Scott Williams (Scarlets) and Rhys Priestland (Scarlets) have agreed regional contracts.
Ospreys tight-head prop Adam Jones is the only one of the six who has yet to agree a new deal with either region or union.
And full-back Leigh Halfpenny will be playing in France with Toulon next season after leaving Cardiff Blues.
Warburton said in June he had
he would be able to continue playing for the Blues as part of the WRU deal.
And his agent, former
reacted to the breakdown in WRU-RRW talks by saying the nation’s players have been “caught in the middle” of the row.
The last “participation agreement” between the WRU and RRW ended on 30 June.
That contract guaranteed the release of players for Wales coach Warren Gatland’s two-week squad training camps ahead of November games, the Six Nations and for the fourth autumn Test which Wales regularly stage outside the approved International Rugby Board window.
If a new deal is not finalised it could mean the regions refusing to release players for Wales’ match against South Africa on 29 November.
Sam Warburton: Rugby row casts doubt over Wales captain