This year's rule changes. The exact wording of the rules hasn't been released, but they hinted that greyshirting and blueshirting may be out the window.
http://www.espn.com/college-footbal...overhauling-college-football-recruiting-rules
"Also bundled in the proposal is the limitation of annual scholarships to 25. This is a move to do away with oversigning and to reduce the practice of grayshirting, a tactic by which schools delay the enrollment of a prospect until the following January so his signing would technically count as part of the next class.
The legislation limits to 25 the number of prospects whose aid is initially offered in the fall term of an academic year. Before, rules limited to 25 the number of prospects allowed to sign from Dec. 1 through May 31. This portion of the changes will affect newcomers in the 2018 signing class."