A few hours later, the Panthers formally announced the end of the coach's nine-year run, in which he led the franchise to its only Super Bowl, saying the contracts of Fox and the rest of his staff will not be renewed after Sunday's game at Atlanta.
"I told John today that I appreciate everything he has done for us over the last nine years, but as happens in this business, it is time for both sides to move in different directions," Panthers owner Jerry Richardson said in a statement released by the team.
Fox's departure hasn't been a secret, and his last full practice at the Panthers' complex was an odd scene with the Meineke Car Care Bowl about to kick off just a few steps away at Bank of America Stadium. Fox gathered his team around him shortly before noon, with a burst of laughter heard from players as they broke toward the locker room.
"It's been a lot of great memories, a lot of fond memories, a lot of great relationships and something I'll cherish forever," Fox told reporters. "Now (I'll) just embark on the next chapter."
Fox was first denied a contract extension after the 2008 season. He entered the last year of his deal this fall after the Panthers began a youth movement that has left them an NFL-worst 2-13.
"It's not new," Fox said of his impending departure. "It's something I've been preparing for actually for a couple of years."
A rift had developed between Richardson and Fox since the Panthers' last playoff game, a 33-13 loss to the Arizona Cardinals in January 2009. Fox was more vocal this season in showing displeasure for several personnel moves that left Carolina short on experience and talent.
The Panthers have the league's last-ranked offense and have locked up the worst record and the No. 1 overall draft pick in April.
Fox, who is making more than $6 million this season, is 78-73 with Carolina, including the franchise's only Super Bowl appearance, after the 2003 season. But the Panthers have never posted consecutive winning seasons under Fox, who inherited a 1-15 team from George Seifert in 2002.
In his statement, Richardson didn't address what he'd be looking for in a new coach. Only Jeff Fisher in Tennessee, Bill Belichick in New England and Andy Reid in Philadelphia have been with their teams longer than Fox, who had been the New York Giants' defensive coordinator before joining the Panthers.
"While we haven't accomplished all of the goals we set as an organization when we signed him in 2002, we have certainly had our share of high moments -- the Super Bowl, two NFC championship games, and a division title in 2008," said Richardson, who hasn't answered questions from reporters in almost three years. "We wish John and his family the best going forward."
There was a light mood around Friday's practice, and cornerback Captain Munnerlyn said Fox never brought up his ouster with the players. Munnerlyn said by phone that the news was "shocking."
"It's sad, and it kind of hurts, too," Munnerlyn said. "These are the guys who have been coaching me since I came into the league last year, so you get close to them. It makes me sad to see them go."
Added tight end Dante Rosario: "It's difficult to see them go. It's not an easy thing to take."
It follows a theme of Panthers lining up to support Fox, who's known for being tough but also as a player's coach. Fox has been able to hold onto the locker room despite his lame-duck status and the team's poor record.
"I'll say this," Fox said before hustling inside after practice, "these guys have stayed enthusiastic and have continued to work very hard all season."
Injuries didn't help Fox's cause this season, as the Panthers tied a team record with 14 players on injured reserve. Fullback Tony Fiammetta became the latest Friday, going on IR with a left ankle injury sustained during a Dec. 19 victory over the Cardinals.
The Panthers signed linebacker Thomas Williams from the practice squad to fill Fiammetta's roster spot. Williams was a fifth-round draft pick by the Jacksonville Jaguars in 2008 and also has spent time with the New England Patriots and Buffalo Bills.
Wide receiver Steve Smith (calf) also is questionable after missing practice Friday, further depleting a Carolina team that had serious deficiencies before it was hit with a number of injuries.
Armed with the No. 1 pick and a new coach, the Panthers hope to make a quick turnaround.
"I guess the owner and the general manager are trying to make this team better," Munnerlyn said, "so we have to put our faith in them."
The Associated Press contributed to this report.