The warning for months from union officials to NFL players has been simple: Save your paychecks because the future is uncertain.
Another warning should come along with it: Remember that nothing lasts forever.
Brett Favre could have saved himself plenty of embarrassment had he heeded those words instead of returning for one last dismal season. Not only did his reputation take a beating, but so did his 41-year-old body.
Favre, of course, is not alone. History is littered with athletes who, for one reason or another, simply couldn't let go.
But when it happens in the violent contact sport that is the NFL, there can be some unpleasant consequences.
That's what makes the case of Tiki Barber so interesting. Barber was the one player who seemed to get it, retiring from the New York Giants after enduring a pounding as an undersized running back in the league for 10 years.
"You start to realize this is a young man's game," Barber said on his way out. "This is for guys who can get hit, knocked up, beat up and be fine on Tuesday."
Four years later, Tuesday has come for Barber. The 35-year-old has filed paperwork to try and play in the NFL again, assuming he can find a team that wants him.
That team won't be the Giants. They wished Barber good luck, saying they will release their rights to him so he can pursue work somewhere else in the league.
Hard to blame them. Though Barber is the team's career rushing leader with 10,449 yards, not many Giants fans will forget his final season in New York, when his mouth may have cost the team a possible shot at the Super Bowl.
He called quarterback Eli Manning's attempts to motivate the team "comical," and wondered out loud why coach Tom Coughlin didn't understand that he needed to run the football for the Giants to win. He also became a lame-duck distraction by announcing he would retire at the end of the season, and a team that started 6-2 ended up 8-8.
He's regarded by many as such a pariah in New York that he was roundly booed when he was installed on the ring of honor at the team's new $1.6 billion stadium. For many fans, the only thing anyone needs to know about Barber is that the Giants finally did win the Super Bowl a year after he left.
None of that was supposed to matter when Barber gave up the final two years of a lucrative contract to embark on a new career. Glib and personable, he reportedly spurned offers from two other networks to sign a deal with NBC that not only landed him briefly on the network's Sunday night football program, but gave him a day job as a correspondent for the "Today" show.
"He's incredibly handsome, he's incredibly charming, he's incredibly personable and he's incredibly smart," former NBC Universal president Jeff Zucker said in announcing Barber's hiring.
For a while it seemed like Barber was everywhere. He wrote an autobiography, became partners in a flavored water company. There was talk of him one day entering politics.
Now he's nowhere. Out of football, out of the job he left the game for.
In a story Tuesday that broke news about Barber's possible comeback, SI.com said Barber reportedly left his wife, Ginny, who was eight months pregnant with twins, for 23-year-old Traci Johnson, a former NBC intern. Last year, NBC cited its morals clause and terminated the contract that reportedly paid Barber $300,000 a year.
The New York Post reported last June that Barber was broke and couldn't pay his divorce settlement with his ex-wife.
Now he wants back in the NFL, and it's easy to see why. The minimum salary for a 10-year veteran is $865,000 and a contract containing some incentives could push that salary even higher.
The question is, who would want him? Old running backs aren't in great demand, especially one who has taken as many hits as Barber.
And, outside of a possible pairing with his twin brother, Ronde, in Tampa Bay, who would risk even the minimum salary on a 35-year-old who was a clubhouse malcontent and has been out of the game for four years?
Barber would be wise to remember his own words when he parted ways with the NFL.
"Always leave them wanting more," he said. "Leave too early rather than too late."
What Barber doesn't realize is that it's already way too late.
Tim Dahlberg is a national sports columnist for The Associated Press. Write to him at tdahlberg(at)ap.org