Adam Schefter explains why teams are complaining that the Packers violated NFL rules by placing Aaron Rodgers back on IR. (1:24)

Multiple teams complained to the NFL last week that the Packers violated the rules regarding players who are eligible to be placed on injured reserve -- and that Green Bay should have to release quarterback Aaron Rodgers as a result, league sources told ESPN.

NFL rules stipulate that a player needs to have suffered a new injury that would sideline him at least six weeks to be placed on injured reserve. If that is not the case, the team is obligated to release the player once he is healthy.

Rodgers was activated off injured reserve and played last Sunday against the Carolina Panthers but came out of the game because he was "sore," according to Packers coach Mike McCarthy.

But Green Bay did not announce its decision to place Rodgers back on injured reserve until Tuesday, after the Packers had been eliminated from a potential postseason spot.

Had the Atlanta Falcons lost to the Tampa Bay Buccaneers on Monday night, keeping alive Green Bay's playoff chances, it's possible Rodgers could have played Saturday night against the Minnesota Vikings. But the Packers opted to shut him down, which teams complained was a violation of NFL rules.

It is not believed that Rodgers suffered any type of new injury against the Panthers.

"Frankly, I don't see any issue with Aaron Rodgers going on IR," McCarthy said Sunday. "My understanding is we communicated, followed the procedures and guidelines that you have to, to put a player on IR. So from our perspective, there's no issue."

If Rodgers didn't suffer a new injury but was placed back on injured reserve anyway, NFL rules stipulate that the Packers would have to release him -- which nobody expects will happen. It is why multiple teams raised the issue. Teams wanted to know why the Packers were being granted immunity.

The NFL referred all inquiries about the situation to the Packers, who have declined comment. But one source said Rodgers wasn't going to be medically cleared to play in Green Bay's next game, and the Packers knew he wasn't 100 percent.

Still, not gaining medical clearance and being placed on injured reserve are two different things -- which is what drew the ire of multiple teams around the league.

Rodgers was placed on injured reserve and missed seven games after suffering a broken right clavicle in Green Bay's game against Minnesota on Oct. 15. In the Packers' loss to the Panthers, he threw three touchdowns and three interceptions -- the first time he has been picked off that many times in a game since 2009.

ESPN's Rob Demovsky contributed to this report.