PUP designations carry different meanings at different times of the year. With that in mind, now is a good time to freshen up on the implications.
Players on PUP lists entering camp continue counting against the 90-man roster limit. They cannot practice while on the list. However, their teams can activate them from the list at any time before the mandatory roster reduction to 53 players, provided the players pass a physical exam.
This year, teams must reduce to 53 players by 6 p.m. ET on Aug. 31.
Players remaining on PUP lists at the reduction to 53 players must remain on the list for their teams' first six games. They do not count against the 53-man roster limit during that time. After six games have passed, players on PUP have a three-week window to resume practicing. Once a player begins practicing within that window, the team has another three weeks to activate the player from the PUP list onto the 53-man roster.
In effect, a player on the PUP list at the reduction to 53 players could return after his team's sixth game or as long as six weeks after that. The NFL had discussed expanding the three-week window for practicing by two weeks. I'm checking on the status of that proposal, which would have required collaboration with the NFL Players Association.
Update: The window has indeed been extended from three weeks to five weeks, according to the NFL.
Thirteen players from the NFC West are on PUP lists. Five others are on non-football injury (NFI) lists. The rules for NFI mirror those for PUP, the difference being that players on NFI lists suffered injuries unrelated to football. For example, the San Francisco 49ers recently activated defensive lineman Lamar Divens from the NFI list. They did not disclose the source of his injury, but teammate Ahmad Brooks had struck him in the head with a bottle in June, according to authorities.