The Detroit Lions only technically had 52 players on their initial 53-man roster, and after a bit of maneuvering that remained the case. The team's roster moves heading into the season opener gave them 53 players on the active roster for the week.
Lions head coach Dan Campbell openly considers the practice squad an extension of the active roster, and an important part of the team. The 53-man roster is a living entity for every team, changed by injuries and whatnot over the course of a season, but that may be the case in Detroit more than most places. And the Lions have some players on their practice squad who could stick on a 53-man roster somewhere this season at some point, if not theirs.
There will be back end of the roster guys for the Lions who will have to keep earning their spot, each and every week, lest they be replaced. And truly, Week 1 will not be a first game of the season mulligan if it's deemed necessary to make a change after.
So these three Lions players are hardly guaranteed to last the season on the 53-man roster after making it initially, before the first game of the season even happens.