Every analysis I read says that Sanders managed to upset Clinton in Michigan because he poured most of his resources there. He could do the same with Ohio but that risks him getting steamrolled in the other 3/15 states.
Sanders could easily spend 40 Mio. $ in the Super 2.0 Tuesday states.
Because afterwards there are only small states for a while and his fundraising would pick up significantly anyway if he does well.
I just realized how obnoxious the Wisconsin TV markets will be following next week.