The 25-year-old was a key part of France's World Cup success this summer but has yet to truly show his best form with United.
Tensions have reportedly been high between Pogba and United boss José Mourinho with his performances lacking the influence that made him United's club-record signing.
Various reports suggest that Pogba is eager to join Barcelona, with his agent Mino Raiola reportedly keen to get him out of Old Trafford.
And former England manager Allardyce told talkSPORT that the Red Devils should let Pogba go before the player becomes bigger than the changing room.
Sell him. I don't think he's a dressing room boy.
The only trouble with today is getting in a replacement, letting a player of that size go without any replacements of high quality.
But, if the reports in the papers are true and whether it's him or his agent or a bit of both, Sir Alex Ferguson would have just said, "see you later".
He would have done that. There's nobody bigger than Man United.