Remember that Moyes is under huge pressure now. That pressure is not just coming from the press, but from the fans. I read this week that the number of fans who thought Moyes should be sacked has gone from 22% at the end of January to 56% at the end of Feb.
(fwiw the story was from the Telegraph and cites a poll by UWS, though I don't read that 'zine myself so am going on the Telegraph's story). That's a critical shift, and I can say I've seen that kind of shift replicated amongst my red mates (mostly match going mancs) and on this site.
Moyes will know that his job is on the line. He won't go before summer
whatever happens, but a dismal performance between now and the end of the season could cost him his job next year.
Moyes has shown himself to be risk averse in his career at Everton and so far at United. I see absolutely no reason to believe he'll go for 4-2-3-1, or bring in Kagawa, or even Wellbeck. If RvP is indeed out of the game, my guess is the following
Smalling---Vidic--Jones---Evra
Valencia---Carrick---Fellaini---Young
Mata
Rooney
Two wingers to help cover attacks down the wings, and just hope Mata can play in Rooney on the counter.
The trouble for Moyes is that if he continues with a risk averse policy it kind of fails to understand something about United, which is that if you're gonna lose, go out with a bang. If he thinks that an unbeaten run of dour 1-nil and nil-nils between now and the end of the season will get fans on his side, he'd be wrong.
What I hope of course is that he thinks "Fek it" and just goes all out attack from now on til the end of the season, scoring and conceding a tonne in the process. But I've been kind of hoping that since the beginning of January and its not happened yet, so no reason to think it'll happen now.