Both players have been linked with moves away from Old Trafford in recent months.
Bruce said in the Guardian: “Once you leave Old Trafford you find it very difficult. It’s a step down.
“Not many have gone on to do well elsewhere and that applies whether you have been a reserve or have been in the first team for 10 years. It is very, very difficult to adjust.
“The modern player must accept that to be involved at the top – especially when they have been involved in five competitions and can win four this season – you don’t have to play 60 games a year like we did.
“It takes about 18 games to win the UEFA Champions League so you need a squad of players capable of handling the big games.”
