Current rules allow the following which is used by most schools.
A special case involves the eligibility of a player who loses the majority of a season to injury. Popularly known as a medical redshirt, a hardship waiver may be granted to athletes who appear in fewer than 30% of team competitions (none after the midpoint of the season) then suffers a season-ending injury. Players granted such a waiver are treated for the purposes of eligibility as though they did not compete in that season.
Most schools use this out even if the player is not truly injured. You can always make up some injury and withhold him from practice. Notice, however, none can play after the mid-season. Forget who it was, but ND had a WR run in for a play without the coach realizing who it was he was sending in. Player lost whole year for one play after mid-season. In the last few years, more teams have gone to 12 game schedules. 30% is now 4, not 3, so increasing the eligibility rules make sense. But nothing is being said about playing after mid-season. Unless that changes, bowls are out.
Personally, don't care if it is 3 or 4 games. Don't want an extension past mid-season. Make teams play with who they have or pay for using an RS. No use helping the talent rich guys who can sub a 5* RB in the last game and not have him lose a year. They will make up an injury excuse for the 3rd string back and use him. Who wouldn't. Doesn't cost them anything.