I'd be surprised if MSU didn't make the playoffs. They need 6 more wins to hit 7 D1 wins and have 9 games left.
SUU, @UNC, UCD, and @Web are likely wins unless they have an epic collapse. So that's 4 likely wins right there.
They'd need to only win 2 of the following games to hit that 7 D1 win mark likely getting them into the playoffs:
@SFA (Without McGhee)
@UND (Without McGhee)
NAU (Without McGhee)
@EWU
UM
If they drop 2 of their next 3 games without McGhee though things become interesting. @EWU is likely a loss so that would mean the game against the Griz would determine their fate
If I had to bet on it, I'd bet they win at least 2 of their next 3 even without McGhee and do end up making the playoffs. McGhee is a very good QB, but even without him the Cats have a solid team and should be able to handle SFA and UND.