"We're all told at some point in time that we can no longer play the children's game," says a baseball scout in the Hollywood film Moneyball.
"We just don't know when that's going to be. Some of us are told at 18, some of us are told at 40, but we're all told."
Rio Ferdinand, at 35 years old, is nearing the time when he'll be told.
Told that he can no longer reach the level required of a centre-half at Manchester United playing in the Premier League. Of course, a swan song in Los Angeles or New York is not out of the question.
Ferdinand has missed the last six games with a knee injury. He's started just twice in the last two months.
After 11-and-a-half years at Old Trafford he is out-of-contract at the end of the season. It is possible, along with Nemanja Vidic and Patrice Evra, he will play his last game for United in the coming months.
Ferdinand is back in training and David Moyes told the Manchester Evening News he is still a "valued" member of the squad:
We will continue to use Rio at the right times and the right moments.
Rio has made a great contribution especially in the first half of the season.
I played him in nearly all the opening games. He was a big part in helping me to settle. He helped me get my feet under the table a little bit.
He has competition for centre half but he is very much valued.
Without a contract offer, Ferdinand will leave in the summer. But he still has a role to play before then.
His partnership with Vidic, the backbone of title- and Champions League-winning teams, may be over. But not necessarily his pairings with Jonny Evans, Chris Smalling and Phil Jones.
United are struggling. An eighth Premier League defeat of the season at Stoke on Saturday felt like rock-bottom again after the optimism that came with Juan Mata's arrival.
It's a moment in which Moyes could do worse than turn to his senior players. The ones who have seen it and done it. Proven winners.
Ferdinand's legs might not be what they were in his prime but there are few players in the Premier League who can call on more experience.
For younger players like Tom Cleverley and Danny Welbeck to look around and see Ferdinand, Michael Carrick and Robin van Persie among their number can only be a boost to their confidence.
It has happened far too few times this season.
Soon, Ferdinand will be told he can't play the child's game anymore. Some are told at 16, some at 18. Others are good enough to carry on until they're 35.
Battling to finish in the top four and still chasing the Champions League trophy, United could certainly do with the experience Ferdinand picked up in those intervening years.