Mike Patterson's agent said that he planned to file a grievance through the NFL Players Association after the Eagles placed his client on the non-football illness list Wednesday.
"This is not how you treat people if you're a winning organization," Peter Schaffer said.
Patterson will lose about $150,000, or 50 percent of his remaining salary, Schaffer said.
Patterson contracted pneumonia last week and required hospitalization. He was home and resting as of Tuesday, according to team trainer Rick Burkholder.
Schaffer said that he spoke to Howie Roseman after he was informed of the move and told the Eagles general manager then that he planned to file a grievance because he believed the defensive tackle likely contracted the illness because of work.
"I think it's pretty clear that he got it at practice or at the NovaCare Complex," Schaffer said. "That's where he spends all his time. That's all he's doing, practicing and working out."
The Eagles released a statement Wednesday evening.
"Our No. 1 priority is to get Mike Patterson well enough to get back on the football field," the Eagles said. "He has worked hard this year to get back, and he has our full support as an organization."
Patterson's season is over. Players placed on non-football illness lists must sit out for at least eight games. This is Patterson's second stint on the list this year. The Eagles placed him on it in late August when it was clear he would not be ready by the start of the season.
Patterson underwent brain surgery in January for an arteriovenous malformation. If he did not return to the 53-man active roster within three weeks after he returned to practice in late October, Patterson would have lost 50 percent of his salary or approximately $1.25 million.
He did return and played Nov. 5 at New Orleans. Patterson has played in five games this season and has been credited with nine tackles and one sack.
Patterson, 29, is the Eagles' longest-tenured player. The team is not expected to bring the eight-year veteran back next season. He has four years left on his contract.
"I told Howie this morning that if he could prove to me that Mike didn't get pneumonia at practice I wouldn't file a grievance," Schaffer said. "He said he couldn't."
Schaffer has had a long-standing relationship with the Eagles. He had lunch with Roseman and former Eagles president Joe Banner every year at the Indianapolis scouting combine.
"I love Howie, but this is wrong and petty," Schaffer said. "To do this to one of your leaders and to a guy that fought back from brain surgery is just wrong."
The Eagles needed a tight end this week after Brent Celek was ruled out with a concussion. So, Emil Igwenagu, a rookie from Massachusetts, was promoted from the practice squad.
Igwenagu was with the team during training camp and the preseason and has been on the practice squad all season. He swung between fullback and tight end during the preseason and caught six passes for 36 yards.
To fill Igwenagu's spot on the practice squad, the Eagles signed defensive tackle Ronnie Cameron. Cameron spent time with the Cleveland Browns and Chicago Bears during the preseason.
Quarterback Michael Vick and running LeSean McCoy were officially declared out for Thursday night. Vick will miss his fifth consecutive game, while McCoy will sit out his fourth straight.
Safety Kurt Coleman was also declared out with a chest injury. Running back Chris Polk is questionable for the second consecutive week with a toe injury.
Guard Evan Mathis and wide receiver Jeremy Maclin are both probable and expected to play.