England's Aviva Premiership clubs will each be permitted one player excluded from the salary cap in 2012.
Premiership Rugby says the move, which the clubs unanimously agreed, will increase capacity for retaining top English talent in addition to attracting leading foreign players.
It will take effect in the 2012-13 season, when the salary cap will rise from £4million next term to £4.26million, and potentially open a door to lure some of world rugby's top stars. The introduction of academy credits from next season though, will effectively take the 2012-13 cap up to a maximum of £4.5m.
Academy credits will see clubs receive a credit within the salary cap of £30,000 per player for including home-grown academy talent in their senior squads.
The maximum benefit for each club in a season will be £240,000, covering eight academy products.
"Based on our collective financial strategy and the continued commitment to developing English players, we have been able to make changes to the salary cap through until 2015," said Mark McCafferty, Premiership Rugby's chief executive.
"We believe this will further strengthen the playing and commercial success of the competition.
"Looking forward, the continuing success of our expansion strategy to 2015 will depend significantly on our development of playing talent to world-class levels, our retention of that talent in England and the continued attraction of some of the world's best players.
"This combination will add significantly to the attraction of our competition to supporters, viewers and partners.
"Our successful growth will also continue to depend on striking the right balance between the investment in playing talent and the continued long-term financial stability of clubs. The clubs have agreed how best to strike the right balance."