With all of the time Christian Mahogany has been out, it's going to be difficult for him to be ready for game action at the beginning of the regular season.
If Christian Mahogany is cleared to practice, it's near certain that the Lions will use at least part of the 3-week window at some point this season, before he's activated to the 53 man roster. He's a rookie, who didn't have any practice reps in training camp. Any rookie in a similar situation would need practice reps.