This just makes logical sense. Miller can't throw and likely won't be able to do so until the summer, so the pool of suitors will be quite small -- and this is if rehab goes to plan.
If Miller moves to H, he'd be helping himself the most by staying at OSU. While every team could use a Miller-type at QB, there are much less that could/would use him at H, whether it's because they don't feature the position or they are more comfortable with their own guys.
The Buckeyes are loaded enough that Miller can get a few drives a game to learn on-the-fly without hurting the team. Frankly, I wouldn't be surprised to see one of Wilson/Marshall moved wide. Miller will have a substantial sample size for the NFL to look at, and we'll have another warm body if the young receivers continue to struggle with their health. Both sides benefit.