Typically there are a few post-spring transfers and ND is banking on that.
The only year they were over going in was 2020 (due to covid kids stayed put more than normal) and that year they put 3 guys on medical scholarships to get to 85, meaning they honored the scholarship, but the kids couldn't play. This might have been legit medical stuff or it might have been creative roster management by ND...one of the guys put on medical was Isaiah Robertson, who tried to grad transfer and keep playing (indicating that he didn't think he had a career-ending injury), but I don't think any other schools took him..