"Ben has terrific ability and needs game experience. Tomasz is also another good keeper," Ferguson told a news conference.
"At the end of the day the two of them will fight it out, I'm sure of that."
"Edwin's not said anything yet about what he intends to do," Ferguson said. "He has come back from his recent injury well. It will be Christmas time or sometime in December when he will outline his plans and how long he will go on. We will await that."
CSKA Moscow's goalkeeper Igor Akinfeev had been strongly linked with a move to United.
"We want to win the group," said Ferguson. "It's a good fixture in that we are already through. It means I can try one or two things. We could easily have an absolute non-event game or it could be the absolute opposite."
