Published Thursday, 05 January 2012
From 2013 the IRFU will only allow one non-Irish eligible player to fill a particular position across three teams - Ulster, Leinster and Munster.
Three of Ulster's tries against Munster last week were scored by overseas players.
Ulster Captain Johnann Muller, who plays at lock for Ulster, might be one of those affected by the rules change.
Leinster also have an overseas player in the same position, but from 2013 this won't be allowed to happen.
Johann Muller said: "For me, if young players can learn from any player, if they can learn from me and become better players in the years to come, that's exactly what I want to do.
"If the Ulster line up in five or ten years time is really good, and I had a little bit of a part to do with that, I'll be really happy and I think yes, it's great for Irish rugby and they want to get it strong and that's exactly what you need to do.
"Still, you probably need a little bit of influence from elsewhere to make sure you get that stepping stone to make sure you build the players for the future."
The new rules also state that once an overseas player's contract expires it cannot be renewed and that position must then be filled by an Irish player.
Furthermore, all players brought in to cover for injuries must be eligible for Ireland, and all foreigners must be signed to play one specific position on the pitch.
Ulster Coach Brian McLaughlin said: "When David and I first took on this job we said that we were going to bring in any foreign players."
"The foreign players will have to be better than anything we've got here and they'll have to be players that we can use, not only to benefit Ulster rugby on the pitch but also off the pitch and the work that the likes of Johann Muller, Pienaar and John Afoa are doing at the minute with our younger squad members, with our academy, it's great and to be fair to them, they would be badly missed."
The IRFU says the changes are intended to develop a more competitive Irish squad for the next World Cup.