The 18-year-old has managed 20 appearances for the City first-team this season, netting five times in the FA Cup and Carabao Cup - but only nine of which have come in the league.
“He's got great potential, but at the end of the day he needs game time," Ferdinand told talkSPORT.
“He's not going to get that at Manchester City. Jadon Sancho didn't, so that's why he left.
“He demanded regular football and decided to go to Borussia Dortmund.
“To be fair he's fully vindicated that decision – he's a £100m plus player now.
“If there's an injury in midfield and they've got a big game I don't see Foden being the man to come in and fill the gap.
“There's no doubt Foden will improve by training with a squad of that quality, but there will come a time when he thinks to himself I want to play first-team football.
“Every footballer has that competitive nature in them and wants to be one of the first names on the teamsheet – Foden will be no different.
“I hope he gets the opportunity do that at Manchester City because it will be great for English football, but the circumstances would need to change."