GREEN BAY, Wis. -- A body pulled from a river in Oshkosh, Wis., Monday has been positively identified as that of 21-year-old Michael Philbin, son of Packers offensive coordinator Joe Philbin, a source close to the family tells ESPN.

Oshkosh police have yet to release the identity of the body. The Packers, who are preparing for Sunday's NFC divisional playoff game game against the Giants, canceled player availability Monday.

Police have been searching for Michael Philbin since Sunday evening. He disappeared at about 2 a.m. Sunday after an outing with friends in the University of Wisconsin-Oshkosh campus area, about 50 miles from Green Bay.

Joe Philbin spent Monday in Oshkosh, where divers recovered the body of a man between the ages of 20 and 25 from the Fox River in the late afternoon after a security guard reported hearing cries for help from someone on the ice. Oshkosh police said foul play was not suspected, but the man's name was being withheld until his family is notified.

Michael Philbin is the second-oldest of six children to Joe Philbin and his wife, Diane.

"The Philbin family's obviously going through a tough time right now, and as we always have, we're a family-first philosophy with our organization, with our program," Packers coach Mike McCarthy said earlier in the day. "So we're supporting Joe and his family the best we can, and we're holding out hope that this comes to a positive conclusion."

The offensive-minded McCarthy calls his own plays and has a hands-on role with game planning, but Philbin's behind-the-scenes detail work with quarterback Aaron Rodgers and the rest of the offense would not be unnoticed. McCarthy said he has contingency plans in place to prepare for Sunday's game if Philbin remains away from the team.

"We're prepared to do whatever we need to do as a staff to make sure our team's ready to go," McCarthy said, brushing aside a question about what the Packers would be missing if it did not have Philbin's input this week. "We'll be ready to go."

Packers and Giants players took to Twitter with supportive messages.

"As children we all have to someday say goodbye to our parents, but a parent should never have to say goodbye to their child," said offensive lineman T.J. Lang, whose father, Thomas, died last week.

Packers defensive lineman B.J. Raji wrote that "life is too short."

"Live in the present," he tweeted.

Giants defensive end Justin Tuck offered his condolences via his Twitter page.

"Our prayers go out to the Philbin family and Packer nation for their loss," he wrote.

Joe Philbin has been with the Packers since 2003 and has been the team's offensive coordinator since 2007. He interviewed for the Miami Dolphins' vacant head coaching job last week.

Information from The Associated Press contributed to this report.