So if the knee injury the third-year guard/tackle sustained in practice on Tuesday is as serious as it looked, it would strike a blow to a unit that only hours earlier McCarthy had called the "one position group that had the most consistent work from practice one through eight."
McCarthy did not have an update on Barclay's status shortly after practice, but it did not look good. Barclay's right knee appeared to give out. He was on the ground for several minutes. He walked to the sideline on his own but then was taken away on a cart.
According to the Green Bay Press-Gazette, Barclay tore his anterior cruciate ligament.
"I was standing right behind him; he got himself in a bad position," McCarthy said.
Barclay was injured while blocking outside linebacker Adrian Hubbard. At the time, he was lined up at right tackle, where has started 21 games (including playoffs) over the last two seasons. Yet during training camp this summer, Barclay has spent more time playing right guard while T.J. Lang rested his sore shoulder the first week.
Although he is listed only as the backup at right tackle on the depth chart the team released Monday night, the reality is that in a game, he would probably be the top backup at a minimum of three positions -- right tackle and both guard spots -- and probably could play left tackle or center in a pinch.
Second-year pro Lane Taylor is next on the depth chart as a backup guard, while Derek Sherrod has worked as the other No. 2 tackle. Combined, Taylor and Sherrod played 20 snaps on offense last season to Barclay's 1,027, which is just another illustration of how difficult it would be to replace Barclay if he is lost for the season.
"Yeah, that'd be tough," left guard Josh Sitton said. "Hopefully that's not the case. But he adds a ton of value to this line. You typically don't get a sixth guy that can play that many positions and has had that much experience with 20 games or started. That will be a big one if he's down, but hopefully it's nothing too serious.”
Barclay is the second Packers' player to sustain a knee injury in the last week. Rookie receiver Jared Abbrederis tore his ACL in practice last week. Abbrederis said Tuesday that team physician Dr. Pat McKenzie will perform his surgery within the next week.
There was one other injury of note on Tuesday. Safety Morgan Burnett did not practice because of an oblique injury he apparently sustained on Monday, when he dropped out midway through the practice. First-round pick Ha Ha Clinton-Dix replaced Burnett at strong safety.