You never know, but I don't see Michigan getting in under any scenario because the Big 10 CG winner should get in ahead of Michigan, and the Big 10 is not getting 3 teams in. Winning the conference championship game is a consideration as is how you are playing at the end of the year.
If Penn State wins, they will have a better overall record than Michigan (11-2 to 10-2), a better conference record than Michigan (9-1 to 7-2), and they will have closed the season having won 9 in a row while Michigan lost 2 of their last 3. Just don't think Michigan's win over Penn State in September trumps all of that. Also, everyone assumes that tOSU is in no matter what, and really hard to justify putting tOSU in the playoff, and keeping Big 10 Champ Penn State out given that they also beat tOSU straight up.
If Wisconsin wins, they will also have a better over record than Michigan (11-2 to 10-2), a better conference record than Michigan (8-2 to 7-2), and they will have closed the season having won 7 in row while Michigan lost 2 of their last 3 (including at Iowa, where Wisconsin won). Again, don't see how Michigan 7 point win over Wisconsin at Michigan back in early October jumps Michigan over the conference champion. If you are going to give credit to Michigan for the OT loss to tOSU, Wisconsin also took tOSU to OT.
Michigan could've lost tOSU, and still got into the playoff, but they couldn't lose to Iowa and tOSU (and play a crappy game against Indiana) and still get in the playoff.