Sam Shields didn't need to watch the film to know he wasn't himself Monday night against the Atlanta Falcons.
The Green Bay Packers' fifth-year cornerback could tell something was off after missing two days of practice last week due to a concussion. After being cleared to practice Sunday, Shields was limited to "jogging" and taking "mental reps." The rest of his work came moments before the game in warm-ups.
The limited snaps resulted in a rusty return against one of the NFL's preeminent receivers in Julio Jones. The Packers held on for a 43-37 win, but not until after Jones caught 11 passes on 17 targets for an eye-popping 259 yards, the most the Packers ever have allowed to a receiver in a single game.
No one was innocent in Green Bay's secondary, but Shields' gaffes were noticeable. He was beaten on Jones' 22-yard touchdown in the fourth quarter and nearly gave up another earlier in the game. Jones bailed him out by failing to get his feet in bounds.
The Packers have steered clear of saying Shields was benched, but the fact remains Davon House played the final 21 defensive snaps, while Shields watched from the sidelines. House fared well against Jones with two key pass deflections down the stretch.
"There was a lot going through my head," Shields said. "It was frustration. You don't want to be on the sideline. Coach made the decision. He made a good decision, put House in there, House made some great plays."
The Packers will be counting on Shields this Sunday against Buffalo, especially with House's status up in the air after injuring his shoulder during his relief appearance. It happened on a contested lob from Matt Ryan that resulted in House's right shoulder landing awkwardly on Jones' knee.
Packers coach Mike McCarthy said House won't practice Thursday. House was awaiting test results as of Wednesday afternoon and said he had more scheduled for Friday.
Regardless of House's availability, it's a given Shields will be back in the starting lineup against the Bills. After signing a four-year, $39 million deal in March, he was off to a terrific start until he tweaked his knee against Miami on Oct. 12, which caused him to crumble to the ground before a play.
He was diagnosed with a strained patellar tendon and missed the next two games. Shields struggled in his first game back against Chicago, the same week Brandon Marshall caught 10 passes for 112 yards and a touchdown. Pro Football Focus saddled Shields for four missed tackles in the 55-14 win.
The Packers reiterated last week they had no problems rolling with Shields if he was cleared for a return, but the cornerback admits it was "very tough" playing without practice. With the continued emphasis on player safety, the activity of players diagnosed with concussions is heavily monitored and restricted.
It was the second concussion Shields has suffered during his NFL career. His first came on the notorious play against St. Louis on Oct. 16, 2011, when Shields attempted to return an interception out of his own end zone.
On Sunday, Shields gave up three catches for 66 yards and a touchdown to Jones, according to Pro Football Focus. A full participant in practice Wednesday and no longer listed on the team's injury report, Shields said his availability this week should help get him back into rhythm for the Bills.
"I needed a couple reps. That probably would've helped out," Shields said. "It happens. I was in there, I got back on the field (and) that was the most important part. I'm getting reps this week and I'll be ready for Buffalo."
The issues that plagued the Packers' defense continued to be a topic of conversation Wednesday. That's what happens when you allow 30 points and 304 yards in the second half of a game that was on the verge of being a blowout at halftime.
The final damage saw a 31-7 lead shrink to a six-point victory and caused the Packers' pass defense to fall nine spots to 20th in the NFL.
After reviewing the film, McCarthy said it was a mixture of poor communication and fundamental breakdowns. They'll need quick corrections working on the short week. Another blossoming receiver awaits them Sunday in Buffalo rookie Sammy Watkins, who scorched Denver for 127 yards Sunday.
Watkins, the fourth-overall pick in May's draft, is on pace for a 1,000-yard season with 58 catches for 822 yards and five touchdowns in 13 starts.
"I understand what happened in the second," McCarthy said. "I will never apologize for a victory in December, regardless of what it looks like. It's a great opportunity for us to learn from. Some of the best lessons you learn in this game are when things don't go right. We'll be a better team because of it."
A healthy Shields would play a big part in a bounce back, especially if House can't go. The Packers say Casey Hayward and Micah Hyde can play on the perimeter, but they've been used in that capacity only in emergency situations.
When the secondary has struggled this year, it's been a collective effort. Jones' biggest play came when covered by veteran Tramon Williams, beating him up the sideline and shaking single-high safety Morgan Burnett for a 79-yard gain.
It would have been a touchdown had it not been for Shields' 4.3-speed stopping him a few yards shy of the end zone.
Another shootout seems unlikely against the Bills' 22nd-ranked offense, but journeyman Kyle Orton has steered an underdog to a victory against the Packers before.
Orton threw for 299 yards and guided the Kansas City Chiefs to a 19-14 win over the Packers on Dec. 18, 2011, effectively ending Green Bay's bid for an undefeated season.
The secondary has plenty to prove and it starts with Shields regaining form. As for what happened against Atlanta, Shields knows "(stuff) happens." Now, it's all about Buffalo.
"I talked to my certain coaches, we talked about it and moved on," Shields said. "But they weren't like, you're benched, you suck. It wasn't like that. They felt it was time for House to get in there. They were being cautious about my head."