More than three weeks ago, the Irish Rugby Football Union (IRFU) signed a deal to pay the €550m bonus offer from the French Super League (CNRS) to all players.
The bonus offer is based on the club’s annual wage bill, with the IRFU providing the remainder of the payment on top.
In terms of money, the bonus would be around €1m a season, which is roughly €10,000 per player.
For the past three weeks, the IRU has been on a high-profile hunt for new signings and has brought in the likes of Joe Schmidt, Conor Murray and James Tracy to help bring in new players.
This year, the club has been able to add to its squad, and has also been able do this despite having a limited number of available players to play.
The Irish Rugby Federation (IRF) announced the signings of Joe Murray, James Tracy and Conor Murray on Tuesday afternoon.
They will all play their first matches for the IRF this weekend in Ireland against the Connacht All Blacks at Kingspan Stadium.
All three players have had an outstanding season, having been linked with many clubs across Europe.
McClintock, who is currently at Scarlets, has been one of the most highly rated players in the game, and the 28-year-old is believed to have been in line to make a move to the IRB this summer.
The 27-year old has been linked to clubs in France, England and Wales.
He was a key part of the England side in their World Cup win in 2014 and has since played for Connacht, Ulster and Munster.
McCrindle will join the Scarlets in the coming weeks, and should form part of a side that could be ready to challenge for a top-four place in the Super League.
Murray and Tracy, who will make their senior debuts next season, have been linked heavily with clubs across the European Union, with both reportedly keen on joining the Scarlet squad.