Fellaini has been troubled by a back problem and he was one of a quartet of senior players to miss training on Monday morning.
Moyes confirmed he was dealing with a "few knocks" ahead of Tuesday's game.
Asked whether those four were the players he meant, the Scot said: "Yes."
United only require a point to seal top spot in Group A, having already secured their place in the knockout stages.
However, after suffering back-to-back home Barclays Premier League defeats in the space of four days, the Red Devils are desperate for a positive result to raise their flagging morale.
"It is tough," said Moyes.
"The expectation here is to win all the games."
Source: PA
Source: PA