Bad news to Dallas fans

[BrudLee]

Dallas Cowboys: Marco Rivera, the ex-Packers Pro Bowl guard who last week received a $9 million signing bonus to sign a free agent contract with the Cowboys, underwent back surgery Thursday in Dallas after experiencing pain while running on a treadmill, sources told ESPN's Chris Mortensen.

Rivera, 32, is expected to be inactive for four-to-six weeks after surgery that repaired a L-5 disk problem, the sources said. He experienced significant pain in a leg when he was running on a treadmill Wednesday morning in Baltimore, where he was honored at the annual Ed Bloch Awards.

Rivera underwent the operation in Dallas and was said to be resting comfortably at Presbyterian Hospital. Rivera is expected to recover in time for training camp in late July, sources said.

A Cowboys spokesman had no comment about Rivera's status.

Peter King has yet to comment on how back surgery will affect Rivera's inevitable Pro Bowl season.