Manchester United boss Sir Alex Ferguson has admitted that he faces a 'dilemma' in deciding whether to start Louis Saha.
The French striker recently recovered from a knee injury and came on as a substitute in the games against Arsenal and Dynamo Kiev.
Ferguson admits that Saha is a unique player, and feels that he is most effective when coming off the bench.
"The dilemma is do we start him or bring him on? If you look at the composition of our side now, he is different from everyone else - so he makes a bigger impact as a substitute, a great impact," he said.
"So therefore at the moment my inclination is to use him as a sub.
"Louis does more for the team in the sense of his physical presence, his speed, his two-footedness and is good in the air."
When asked if Saha was happy with being primarily used as a substitute, Ferguson said: "Yes, yes he is fine."
The Scot also expressed his belief that it is near impossible for a player to play 40 games in a season.
And Ferguson emphasised the importance of rotating his side in order to keep his starting XI at an optimal level.
"We are managing in the right way. I don't regard anyone as a 40-game player. Simply because in the demands of the game and the speed of the game we are involved in, you're not going to be playing them all," he added.
"That is why we have got a squad. Along the way you know that you are going to be making changes.
"And you hope that because we think we have a good squad, one it keeps them all involved, and two it gives them the appropriate freshness for the challenges we have."