Leinster confirmed Robbie Henshaw would be joining them on Tuesday, but what does it mean for both provinces?
Tuesday was a good day for Leinster rugby, after what has been a very turbulent and difficult start to the season.
The departure of Matt O'Connor and the arrival of Leo Cullen at the end of last season marked a big change for the province, and that has been borne out by the results both in the European Champions Cup and the Pro 12.
The signs of a World Cup hangover were evident as Leinster limped out of European rugby's premiere competition, struggling to find any real rhythm or form as they were outplayed by Wasps, Bath and Toulon.
The introduction of some of the province's younger talent seemed to dust off the cobwebs a bit as Cullen looked to impose his style on the squad, and out of the darkness came players like Josh van der Flier and Garry Ringrose who lead a fantastic display against Bath in round five, with three newcomers in the front five.
At the time, Leo Cullen described that decision to field academy players as "an investment in the future", and this Tuesday, the province moved moved to make that future less a destination and more a reality with the contract renewals of 17 players, and two further signings.
While lock Ian Nagle was added, the move that has grabbed all the headlines is Robbie Henshaw swapping life at the Sportsgrounds for the RDS.
An Irish international and still just 22-years-old, Henshaw's move has not come out of the blue, as there had been rumblings for quite a while that Leinster were chasing his signature. While the move is good news for Cullen and his squad, Connacht are once again, as they were with Sean Cronin and Mike McCarthy, watching their most talented players being snapped up by Leinster.
Speaking to the Newstalk Monday Rewind podcast earlier this week, Rob Murphy of Galway Bay FM revealed that while fans wish him well, they would prefer to see Henshaw leave Ireland rather than going to another provincial side.
"People are going to find it hard that he's going to be playing with another province next year, and I have to say it would be easier for Connacht rugby people to take this if he was going abroad, because it would be a sense of those inevitable things that's happening in rugby right now.
"The money is just better in France and England. But in this case, in this scenario, this is another province and this is a real feeling of that province asserting its advantage over Connacht".
The worry for Pat Lam is that this pulls the rug out from underneath him as he was in the process of building something at Connacht. The side are currently second in the table and in the middle of their best season to date in the Pro 12.
Speaking about the departure, the Connacht head coach said that it was "disappointing but it’s the nature of professional rugby". Lam emphasised how they have been building a collective project, but there's no doubt that there will be a huge gap left to be filled at 13 now that Henshaw is departing.
As a leader for the province, the side's record without the Athlone native this season will make worrying reading for Connacht fans. After injuring his hand in the win over Munster at the end of November last year and missing six weeks, they went on a losing run which saw them defeated by Cardiff, Ulster and Leinster. He returned in the victory over Scarlets at the end of January.
While that's a small sample size of games, and those are undoubtedly difficult fixtures, it's an unpleasant trend. If Connacht want to make real strides and attract the players who can propel them even further off the back of this extraordinary season, they need to hold on to their best talent.
While Henshaw could have stayed and been an inspirational touchstone for Connacht, a shining example of the levels those who come through the youth setup there can reach, his departure may do more harm to the province than his staying would have done good.
Given his talent, the centre is unlikely to fall through the cracks at Leinster as happened to others (such as Fionn Carr) after moving east, but there will be repercussions for some of the aforementioned young players coming through at the RDS.
The news of Henshaw's signing was welcomed by Brian O'Driscoll, who has previously let his feelings be known on the the talent he believes Ringrose has.
However, speaking on Monday Night Rugby on Off The Ball, Johne Murphy stated that, with the amount of centres already at Leinster, whis wouldn't be best move for Henshaw or Leinster. Stating that Ringrose "seems to me to be the real deal", he believed his development could be slowed if not stopped by the competition between three or four players for the two spots.
"It just gives them a lot more options. But if everyone is fit, it does become more of an issue for Leo [Cullen] to try and maintain and make sure that he's getting the best team with the best partnerships out there, and that everyone's playing to the benefit of the national side".
George Hook, who spoke about the potential move several weeks ago, highlighted that money was not an issue given Henshaw's central contract, but rather a trend has evolved that moves players down this path with alarming regularity.
"What kind of message is the IRFU sending to Connacht players and supporters if, as soon as there is a hint of success, the best young players are stripped away and packed off to other teams? How are Connacht supposed to develop and improve if they are continually treated like a feeder farm for their provincial rivals?".
He added that "because Leinster click their fingers and because the IRFU is not strong enough to stand over Connacht's development, the brightest star is being whisked away".
While there seemed to be a recipe for success in place under Lam for Connacht, they have instead found themselves paying the price for overachieving.