The 23-year-old Barclay took over at the position after veteran T.J. Lang went down with a left ankle injury with 6:42 left in the first half of Sunday's 23-14 victory over the Minnesota Vikings.
Coach Mike McCarthy said Barclay did well.
"I thought he did a nice job - pretty much what I thought last night when I left here," McCarthy said Monday during a news conference at Lambeau Field. "(When) he went into the game, we tried to protect him a little bit there in the 2-minute drive. Then at halftime, we made some protection adjustments.
"I thought in the run game, he was physical. That's a trait that we really like in Don. I thought the pass protection, a lot of his (mistakes) were technical. I thought he did a solid job. When a rookie comes in for his first time in game action and you're able to keep playing throughout your game plan, I think that's a big credit to him."
Now, the Packers must decide if Barclay played well enough to merit starting Sunday night at home against Detroit.
"That was his first real playing time. He's been on some special teams a little bit at times throughout the year, but it was his first time playing a lot on the line," offensive coordinator Tom Clements said of Barclay. "He went in and did a good job. He wasn't perfect, wasn't expected to be perfect, but he's a battler and he did well.
"He's on the roster for a reason. He earned his way on the roster and we always say when someone has a chance to play, they have to step in and do the job. He did that."
Lang had moved to right tackle from his customary left guard spot on Nov. 4, when starting right tackle Bryan Bulaga, the team's 2010 first-round draft pick, suffered a dislocated hip that landed him on season-ending injured reserve.
If Lang is able to play Sunday night, he could return to his left guard spot and Barclay could get the nod at right tackle. Evan Dietrich-Smith, who has been starting at left guard since Lang's move, would then return to being the first lineman off the bench. Or, Lang could remain at right tackle, Dietrich-Smith could stay at left guard and Barclay could return to the bench.
If Lang can't play, the Packers' decision would be made for them. Barclay would make his first NFL start and Dietrich-Smith would remain at left guard.
Lang's sprained ankle was one of two injuries to starters the banged-up Packers suffered against the Vikings, as wide receiver Jordy Nelson left after the second offensive series with a strained hamstring. Coach Mike McCarthy said Monday that the injuries "are not of serious nature" but said Nelson would be "pressed hard to play this week."
As for Lang, McCarthy said, "I feel probably a little bit better about T.J. than I do about Jordy," but the coach admitted he didn't know if Lang would be ready to play against the Lions, so Barclay will get snaps at right tackle when the players return to practice on Wednesday.
The only other offensive lineman on the 53-man roster as of Monday night was Greg Van Roten, another undrafted rookie free agent. The Packers have two linemen on their practice squad: seventh-round pick Andrew Datko, a rookie tackle, and Joe Gibbs, a first-year guard.
"The first couple of plays was (I) kind of getting used to it. And then the second half I think I settled in and I got comfortable with it," said Barclay, who'd been a three-year starter at left tackle at West Virginia and made the team coming out of training camp. "The first play was maybe a little tunnel vision. I was just out there. It happens to everyone. But after that I got comfortable.
"You know, a couple plays probably weren't as pretty. But every play I was out there fighting my butt off and that's what it's all about."
The other issue the Packers must consider is how playing an undrafted rookie at right tackle might prevent them from doing what they prefer to do offensively. The coaches schemed to give Barclay help with a tight end or a running back on most pass plays against the Vikings, and both McCarthy and Clements acknowledged that Barclay was appreciably better as a run blocker than pass protector.
"Pass protection is probably a little harder than run blocking, especially at this level," Clements said. "But he did a good job."
The Packers like to use spread formations with quarterback Aaron Rodgers in the shotgun in an empty backfield, so keeping an extra tight end or fullback John Kuhn on the field to help with protection takes that away. At the same time, protecting Rodgers, who'd been sacked an NFL-high 37 times entering Sunday's game but was sacked only twice by the Vikings, is the first priority.
"Anytime you can keep the quarterback upright and completing passes, I wouldn't say that's counterproductive," Clements said. "If we had our druthers, we'd tell (opposing defensive linemen) not to rush at all and just (let us) stand back there and throw it."
Since that's not an option, the Packers may have to sacrifice for protection, regardless of who's playing right tackle.
"It may (limit the offense)," Clements admitted. "But if things we want to do, we're having trouble executing for one reason or another, it doesn't make sense to try to do them."