Wide receiver Jordy Nelson will start training camp on the physically unable to perform list. (PHOTO: Green Bay Packers Facebook )

On the eve of the opening of training camp, the Packers made several roster announcements.

Wide receiver Jordy Nelson, tight end Jared Cook, receiver Ty Montgomery, guard T.J. Lang, center Corey Linsley and linebacker Sam Barrington were placed on the physically unable to perform when players reported to Green Bay’s facilities on Monday. Head coach Mike McCarthy said in his season-opening press conference that he wasn’t ready to discuss player injuries because he hadn’t yet seen the team’s medical report.

Nelson, who missed all of last season with a torn ACL and is considered the Packers’ best pass-catching weapon, had said during offseason minicamps that he was impatient with being held back and was itching to return. Cook underwent foot surgery in the offseason, Montgomery had ankle surgery and Lang had shoulder surgery, while Barrington is coming off a foot injury that caused him to miss almost all of last year. Linsley’s injury isn’t known for sure, but it’s believed to be a hamstring issue.

All six players on the PUP list still count against the 90-man roster. They can be activated at any time during the preseason, but once the regular season starts, players still on the list must sit out at least the first six weeks before being eligible to return.

The Packers also released two players Monday, putting their roster – for now – two under the 90-man limit.

Green Bay cut running back Don Jackson and defensive end B.J. McBryde, general manager Ted Thompson announced. The team has 88 players on its roster heading into the first practice Tuesday morning and could either leave the two spots open or add players via free agency or a trade.

Jackson (5-foot-10, 208 pounds), an undrafted rookie out of Nevada, signed with the Packers on May 6. McBryde (6-5, 303), a first-year player from Connecticut, had been with Green Bay since being added to the practice squad on Nov. 18, 2015.

McBryde participated in Packers minicamp earlier this year and Jackson joined shortly after the 2016 NFL Draft. Jackson was seen as a promising player who was in the mix for the No. 3 running back job. The team did not specify the reason for releasing the players, but there’s a good chance both failed their physicals upon reporting for camp.

Fan-favorite fullback John Kuhn remains unsigned.

Green Bay is one of the first teams to kick off training camp, thanks to its participating in the Hall of Fame Game against the Colts in Canton, Ohio on Aug. 7. The Packers will play five preseason games instead of the customary four.