The Patriots have several players who won't be ready to practice when training camp begins on Friday. They are:

Rob Gronkowski (TE) Declared physically unable to perform
Julian Edelman (WR) Declared physically unable to perform
Jake Ballard (TE) Declared physically unable to perform
Mark Harrison (WR) Declared non-football injury
Armond Armstead (DE) Declared non-football illness
Matt Stankiewitch (C) Declared non-football injury
Nick McDonald (G) Declared physically unable to perform
Kanorris Davis (DB) Declared non-football injury
By being placed on the PUP or non-football injury/illness lists, the players cannot practice with their teammates but can work out with the team's trainers at camp. They can be removed from the lists at any time during training camp.

Seeing Gronkowski and Edelman on the PUP list isn't a surprise. Gronkowski is five weeks removed from back surgery to repair a herniated disk, which generally takes 12 or more weeks to rehab. The bigger decision will come before Week 1, when the team must decide whether to keep Gronkkowski on the PUP list. If they do, it will keep him out for the first six games of the regular season.

Edelman, who will need to take a bigger role in the offense this season, is coming back from a broken foot suffered in December. The Patriots are likely just being cautious with Edelman by placing him on the PUP list to start the season.