CLEVELAND, Sept. 10 (UPI) -- The National Football League is taking a look at whether the New York Jets violated its injury reporting rules last year regarding quarterback Brett Favre.

Farve, who played for the Jets last season and signed with the Minnesota Vikings for this season, told reporters in Minnesota Wednesday he and the Jets coaches and management knew he had a torn biceps tendon during the last five games of the 2008 season. The Jets didn't put Favre on their injury report during that span.

Cleveland Browns Coach Eric Mangini, who was the Jets' coach last season, indicated this week he knew of the injury, The Plain Dealer reported Thursday.

"We are following up on Favre's comments and looking into it," NFL spokesman Greg Aiello told the Cleveland newspaper.

Jets General Manager Mike Tannenbaum told reporters he was responsible for Favre's absence from the injury list.

"As GM of this team, I should've handled that differently and listed him on the report," Tannenbaum said. "We didn't because he wasn't getting treatment every day. We knew he was going to play. But, looking back on it, I should've listed him as probable."

If the NFL decides penalties are in order, they would affect the Jets and not follow Mangini to Cleveland, The Plain Dealer said. Mangini told the newspaper he follows the NFL's rules.

"I can tell you that we always fill out the injury report by the guidelines set by the NFL," Mangini said. "That was true there and will be true here and will be true every week of the season."