Recent reports have claimed a number of United’s top stars will consider their futures at the club if they do not qualify for Champions League football this term.
The likes of Paul Pogba, David De Gea and Romelu Lukaku have been linked with moves away from United this summer, with Ole Gunnar Solskjaer keen to revamp his squad.
Solskjear gave the club a huge morale boost when he replaced Jose Mourinho in December, but the Red Devils have slipped back into their familiar slump in recent weeks.
United have lost six of their last eight games in all competitions, including a 4-0 defeat to Everton on Sunday.
And FA Cup winner Coppell, who spent nine years at Old Trafford, has urged the club to clear out any players who are not giving their all for the famous shirt.
Speaking to talkSPORT host Jim White, the former United man said: “There’s no real consistency now and rotation is such that it’s hard for any players to really cement their place in the team.