Ballard, Edelman, Gronk open on PUP

The Patriots have placed tight ends Rob Gronkowski (forearm/back) and Jake Ballard (knee) and receiver Julian Edelman (foot) on the active/physically unable to perform list, meaning they are not yet cleared to practice.

They can be removed from the list at any point, but the designations provide some early context as to where they stand in their recoveries from surgery.

Gronkowski’s status is no surprise. The bigger question remains if he will be ready for the season opener Sept. 8 at Buffalo after undergoing four surgeries on his left forearm this year and a back surgery June 18.

Ballard had ACL and microfracture surgery in February of 2012 and was a limited participant in spring camps. He is a top candidate to serve as a backup to Gronkowski.

Edelman, whose 2012 season ended in December because of a foot injury, had a "clean-up" surgery this offseason that knocked him out of spring drills. Given the questions the Patriots have at receiver, and Edelman's background in the system and rapport with Tom Brady, Edelman appears to have a big opportunity ahead for him when he returns to full health.

In addition to Ballard, Edelman and Gronkowski, reserve offensive lineman Nick McDonald was placed on the active/PUP list. McDonald, whose flexibility to line up at center, guard and even tackle makes him a valuable reserve, was held out of spring drills due an undisclosed ailment.

Elsewhere, defensive lineman Armond Armstead was placed on the non-football illness list, while rookie safety Kanorris Davis and rookie center/guard Matt Stankiewitch landed on the non-football injury list.

There is a difference between the active/PUP list for training camp and the reserve/PUP list during the regular season.

A player on the active/PUP can be removed at any time, while a player on the reserve/PUP list is required to miss at least the first six weeks of the season.