The Scotsman was left red faced after United paid £89m for the midfielder after he was released from the Red Devils in 2012.
When asked at a speaking event why Pogba was allowed to leave the club for free, the retired boss replied: "Paul Pogba? He had a bad agent. A s*** bag"
"Paul Pogba was well known to us. We knew he was a good player. He's still a good player."