According to various Twitter, internet and published reports Pro Bowl tight end Rob Gronkowski was among eight Patriots players placed on either the active PUP or NFI lists on Monday.

Gronkowski was expected to open camp on the physically unable to perform list after undergoing offseason surgery on both his forearm and, more recently, his back.

Joining Gronkowski on PUP are wide receiver Julian Edelman, tight end Jake Ballard and offensive lineman Nick McDonald. Edelman is returning from a foot injury that kept him out for all of OTA and mini-camp practices, while McDonald also missed time on the practice field this spring.

The Ballard listing may be the most concerning as he was on the field throughout OTAs and mini-camp as he returns from a torn ACL and other knee injuries suffered against the Patriots as a member of the Giants in Super Bowl XLVI in February 2012. Ballard seemed to limp and lack fluid movement this spring, and the fact that he's unable to perform a year and a half removed from his injury is somewhat surprising.

Players who open camp on the active PUP list are the only ones eligible to open the season on the reserve PUP list, which would eliminate them from at least the first six weeks of the season. Players can be removed from the active PUP list at any point during the summer.

Also on Monday New England reportedly placed defensive lineman Armond Armstead on the active NFI list for a non-football illness. The former USC star and CFL import had been practicing during the spring and is expected to compete for a job along the defensive line. He has a history of heart problems after a heart attack cut his USC career short, leading to a lawsuit against the school and his ending up in the CFL for a season before signing with the Patriots as a free agent this spring.

Three other players were placed on the traditional NFI list, non-football injury, including rookie wide receiver Mark Harrison, rookie defensive back Kanorris Davis and rookie offensive lineman Matt Stankiewitch. All three apparently failed their initial camp physical due to an injury not suffered in the realm of their football work with the Patriots this spring/summer. Harrison joined the Patriots with a foot injury.

As with PUP, the NFI players can be removed from the list at any point this summer.