The Manchester United manager, Sir Alex Ferguson, has said that next ­Sunday's Premier League match against Chelsea at Old Trafford will dictate the strength of his starting XI for tomorrow's FA Cup third-round tie against Southampton at St Mary's.

United will play at least seven fixtures in January, including a two-legged Carling Cup semi-final against Derby County. ­

For tomorrow's game Patrice Evra is suspended, Rio Ferdinand is injured and Carlos Tevez is in Argentina attending to a family matter and Ferguson is considering resting ­Cristiano Ronaldo. The ­manager intends to utilise all of his squad this month in order to keep United ­challenging on all fronts.

"We've got a big month ahead and the key is going to be how I navigate it with the 23 players I have," he said. "All of those players are going to have to play their part, particularly against ­Southampton and in the two legs against Derby.

"Obviously there is a big game against Chelsea coming up next Sunday, which I've got one eye on, so it's a busy spell we've got coming up and we have to give careful consideration to the teams we pick."

United are still in contention in four ­competitions and Ferguson said he was determined for that state of affairs to continue, despite the draining effects of so many extra fixtures.

He said: "We're competing for all four. The FA Cup is different altogether, though, because it's partly about luck, you've got to remember that. We experienced it last year in the quarter-finals against ­Portsmouth, where we didn't carry any luck [and lost 1–0]. You always want a home draw but Southampton have got that and it's an advantage to them. It's a good stadium at St Mary's, a nice pitch, and they are a young team. Their coach [Jan Poortvliet] has done a great job considering he doesn't have any money."