According to Eric Hansen, his feel from the coaching staff was that Gilman was the best safety on the roster and would have started this year if not for the NCAA's decision. The reason the coaching staff didn't talk him up throughout summer and fall camp was specifically because they wanted to operate on the assumption that the NCAA might come back with a ruling against Gilman playing this year. Had they touted Gilman during that time it would have seemed like a big blow against the defense when the NCAA came up with their ruling.
Here's a link to an article Hansen wrote regarding Gilman:
https://www.ndinsider.com/football/...cle_704683e6-8cff-11e7-8839-17ace5af03c3.html
And here's the pertinent paragraph:
Gilman won’t play Saturday, however, when the Irish open the 2017 season against Temple at renovated/reconfigured Notre Dame Stadium. Had Navy’s second-leading tackler in 2016 been granted eligibility, the 5-11, 199-pound sophomore likely would have been a starter at free safety.