Manchester United will turn to Rio Ferdinand to marshal their defence against Otelul Galati in the absence of the suspended captain, Nemanja Vidic, but Sir Alex Ferguson has told the player his future at the club may be that of a squad player.

Ferdinand, 32, has found his starting place alongside Vidic increasingly under threat due to injuries and the emergence of the younger defenders Chris Smalling, Phil Jones and, to a lesser extent, Jonny Evans.

The Manchester United manager, Ferguson, said he had told Ferdinand that he may need to accept being part of a regularly rotated central defence. "I explained to Rio the other day that it's simply we have two young centre-halves coming through and I'm very glad to have the four of them and I hope I can keep the four of them for a long time," said Ferguson.

"Rio's almost 33 and he's obviously lost a yard of pace he had five years ago but that doesn't mean he can't tailor his game in a different way – where he used to rely on pace, he doesn't do that now, he can't do that any more.

"We've all faced that decisive moment in your careers when you realise you have to change your game. I did it myself as a player … Rio will do the same and he will be fine."

Ferguson said the England defender still had a "big part" to play at United, where the likes of Ryan Giggs and the now retired Paul Scholes have perfected the art of prolonging their careers at the highest level deep into their thirties.

The midfielder Tom Cleverley has been ruled out of Wednesday's match with an ankle injury, joining Smalling and the winger Ashley Young on the sidelines.

The English champions are second in Group C on five points, two behind Benfica and one ahead of third-placed FC Basel. Galati have yet to get off the mark.