Bradley suffered the injury in the Eagles' Sunday night practice, a source told the radio station, but was able to walk off the field after tackling another player.
Upset by reports that Bradley could be done for the season, Eagles coach Andy Reid said Monday he's not talking about it.
After practice, Reid criticized the media instead of discussing the injury. He said some reporters violated his "pact" with them, which Reid said dictates that reporters ask only him about team injuries, not players or other team personnel.
"We won't talk about injuries today," Reid said. "Some of your colleagues here decided that they would go to the players and/or other personnel here and ask about injuries. I made a pact with you guys when I first got here that I would disclose to you the injuries -- just stay away from the players, stay away from other personnel in the organization, and I would take care of you with that. That part was breached."
Asked why he decided to punish the entire press corps, Reid said, "That's the way it works. Peer pressure is the best pressure there is. You can work it out with your colleagues."
Reid did acknowledge Bradley's absence from practice.
"He did not practice today, and that's where I'll leave it," said Reid, who would not say when he will again discuss injuries. "When I decide that people can abide by the rules, I'll do that."
Bradley also declined to discuss the injury, deferring to his coach.
"I think he's pretty adamant about not addressing the issue," Bradley said.
While Reid and Bradley declined to talk about Bradley's absence, other players did.
"Stu was our starting linebacker, so it's a blow," safety Quintin Mikell said. "But it's the NFL. We got to have guys that are ready to step up, and I believe we have those guys."
Said linebacker Chris Gocong: "Obviously it's really unfortunate, but that's football, and you really do have to roll with the punches and stay on your toes."
Bradley, a third-round pick in 2007, had 151 tackles in his first full season as a starter last year. He's the primary signal-caller on a defense that already lost veteran safety Brian Dawkins in free agency.
Bradley's backup is second-year pro Joe Mays, who practiced with the first team on Monday. The Eagles also have veteran Omar Gaither, who started 16 games at middle and weakside linebacker during the 2007 season.
"You've got two guys that can do a good job there with Mays and Omar," Reid said. "We'll look at that as we go down the road here."
The Eagles had invited fans to attend the practice Sunday, known as "Flight Night," at Lincoln Financial Field.
Information from The Associated Press was used in this report.