I would say that given it is an Ivy, you will have a better shot than you would at most other schools. That being said, the kids heading to Ivys for baseball still hit .400 in HS in tougher conferences and pump 87-90 regularly. They are playing travel ball over the summer and used to seeing 85+ on a daily basis.
The good news for you is that they'll never turn down money, so all you have to do is get to a camp to be seen. The camps are a mixed bag in terms of talent. Some kids will show up throwing 86, others will be throwing 74. When the scrimmages start, its all random. It's worth a shot. Maybe you run into some kid throwing 78 and you kill the ball. If they like your swing and mechanics, maybe theres something there. Explain that you're looking to transfer and already have borderline grades. It's possible that if it goes well that they ask you do head to a JUCO for a semester and then bring you in for the spring. Something your parents can probably get on board with.
The hard part is getting them to notice you. Email, have your HS coach call, whatever it takes. Because you can show up for a camp, go 4-4 and it won't matter if nobody is paying attention.
If none of that works, then just apply as a regular student and try to walk on. But once you're at Michigan you probably won't want to leave.