But the manager said he would "seriously consider" picking Shinji Kagawa in midfield after his man-of-the-match display against the Villans.
"We have defensive issues, undoubtedly," Moyes said. "But I won’t be giving out my team today, certainly not to Bayern or you either, as everybody is well aware we will have to make one or two changes.
"Shinji is a really important player to us. We like him a lot and he gives us something different. He's certainly in our thoughts for tomorrow night's game."
Asked if he would instruct his United team to take the game to Bayern in the first leg, Moyes replied: "It's an obvious thing to say but it's a two-legged tie and we have to make sure both games are important.
"We’re mindful we want to go to Germany with every opportunity to go through so there’s always a bit of caution in the first leg. But we’d love to go to Germany with a win under our belts because it would set us up nicely.
"Bayern were a very good side last year and won the Champions League. They had a good team and have looked to add to that again this season. They have a new manager and we congratulate them on winning the Bundesliga.
"They are probably the side most people have looked to recently but we have to get a good result to take to Germany and we will try to do that."