Sources close to George North feel he has been 'hung out to dry' by Northampton interim boss Alan Gaffney, who suggested the Wales winger did not want to play against Sale.
North, 25, was released from Wales' camp during the Six Nations off-week but was not available for his club.
Some of Northampton's management are believed to be privately furious.
North is understood to have had a deal with previous boss Jim Mallinder that he would not play on rest weekends.
It appears Gaffney either was not aware of or did not honour this agreement, with sources citing a lack of communication between all parties.
"We picked a side that actually wanted to be out on the pitch," Gaffney told BBC Radio Northampton following the 34-25 defeat by the Sharks.
North, who has been at Northampton since 2013, will be leaving at the end of the season to return to Wales and has been tipped for a switch to Scarlets, although his immediate future at Saints is now thought to be in question.
His first contract at the Gardens granted him "full release" for Wales duty, including "out-of-window" Test matches.
This led to Saints being fined £60,000 in December 2013 for contravening Premiership Rugby rules and allowing North to play against Australia.
Bath were fined the same amount at the end of last year for releasing Taulupe Faletau to face South Africa, which also fell outside the World Rugby-sanctioned international window.
Because of the formal agreement between the Welsh Rugby Union (WRU) and the Welsh regions, Wales head coach Warren Gatland can decide which players to release for club duty during the Six Nations.
However, there is no such agreement between the WRU and English clubs, which means Wales are obliged to release those players from camp during rest weeks.
The onus then falls on the relationship between the individual player and his club as to whether he plays.
North, his agent, the WRU and Northampton have all declined to comment, with all sides reluctant to get caught in a war of words.
Wales face Italy in Cardiff on Sunday, with North, who has 71 caps, set to be involved after coming off the bench in the defeats by England and Ireland.