Munster are understood to be furious with the IRFU's decision not to offer Donnacha Ryan (right) a central contract, which resulted in his head being turned by Racing 92.
Ryan will join Ronan O'Gara at the French club next season and behind the scenes Munster are unhappy with how the situation has played out.
The issuing of central contracts lies in the control of the IRFU's high performance director David Nucifora and the Irish Independent understands that the union cited Ryan's age as the main reason not to renew his deal.
Munster are angry with the reasoning, given that Ryan is only four days older than Jamie Heaslip, who had his national contract extended last month.
Ryan, like Heaslip, turns 34 in December, but given his outstanding performances in the Six Nations, his departure will come as a significant blow.
Munster offered Ryan a contract which was shy of what the IRFU could have put on the table, but moving to Racing will certainly increase his salary.
Ireland desperately missed Ryan in their defeat at Murrayfield and it was telling that Joe Schmidt dropped Devin Toner for the final game against England, and not the in-form Tipperary native.
The two-year move to France will signal the end of Ryan's international career, as he replaces Ali Williams at Racing. Leone Nakarawa is also expected to leave, which would free up a considerable amount of their wage bill.
Ryan didn't feature in Munster's facile 50-14 win over a hapless Zebre, but he will return to the starting XV for Saturday's Champions Cup quarter-final clash against Toulouse.
Both Ronan O'Mahony and James Cronin did their hopes of inclusion no harm with two tries each, while Niall Scannell, Tommy O'Donnell and Rory Scannell also crossed.
However, Rassie Erasmus is demanding improvements from his side for the visit of Toulouse.
"I think we will have to make a step up in every area for next week. Toulouse is definitely a world-class team with world-class players, players who can do fantastic things at any moment," he said.
Zebre: D Berryman; K van Zyl (G Palazzani 66), T Boni, T Castello (M Pratichetti 72), L Greeff; S Bordoli, M Violi (C Engelbrecht 72); B Postiglioni (A De Marchi 28), O Fabiani, B Le Roux (G Roan 63); G Koegelenberg, V Bernabò (capt) (J Furno h-t); M Mbandà, D Minnie (S Tobias 68), F Ruzza (P Ceccarelli 76)
Munster: D Johnston; D Sweetnam, J Taute (D Goggin 66), R Scannell, R O'Mahony; T Bleyendaal (B Johnston 51), D Williams (A Lloyd 60); D Kilcoyne (J Cronin 51), N Scannell (R Marshall 63), J Ryan (S Archer 65); D O'Callaghan, B Holland (D O'Shea 70); P O'Mahony (capt), T O'Donnell (C Oliver 57), J O'Donoghue.
Ref: S Gallagher (IRFU)