If Sam Shields walked by on the street, you might think he was a college student. He's so quiet, even his laugh is polite. If he has any swagger it's horribly unapparent.
Dressed in jeans, casual shoes and bundled against the cold in a simple brown jacket, he leaves Lambeau Field with his head down and hands punched into his pockets looking nothing like Green Bay's answer in the secondary.
And yet since his return Dec. 9 from an ankle injury, Shields has two interceptions in three games, his first sack in nearly two years and seven passes defensed, just a few stats to tell of his big hits, inseparable coverage and feisty nature in no man's land.
He came back from the injury a day after his 25th birthday and appears to be a more well-rounded player since he helped this team win the Super Bowl following the 2010 season, when he was an undrafted rookie free agent out of Miami.
Shields grabbed his latest interception last Sunday when he pounced on an underthrown ball by Titans quarterback Jake Locker. The third-year cornerback had studied all week and realized he needed to get his head around quickly against Tennessee whenever the Titans threw the deep ball.
"And that's what I did on that play," said Shields. "It was underthrown and I kind of did an awkward turnaround. I stuck my hand out."
The sack was basically a gift wrapped by Packers defensive coordinator Dom Capers, who called No. 37 for a blitz.
"That's one of the calls I love - I love to go in there and get the quarterback," said Shields.
How interesting is that? Sacks require a certain nature in a defender, one that the Packers hoped to draw out of their speed demon from Sarasota, Fla. After all, the man only had one career sack before that - in the playoffs in 2010. One.
Rewind the calendar to 4 1/2 months ago, when it was noted that Shields wasn't having the best training camp. He might have been peeking in the backfield. It sure looked as if he was getting beat deep. When the coaches auditioned Jarrett Bush, Davon House and even rookie Casey Hayward, Shields' future looked questionable.
Three days ago, Shields shrugged it off as simple competition.
But veteran left cornerback Tramon Williams said Shields had another assignment, one that was under the radar but took precedence over everything else.
"The only thing that was ever questioned with Sam was his physicality," said Williams. "The kid has all the ability in the world. Obviously he's not the biggest corner, but when you have to put your head in there, that's what they want to see."
Williams, listed at 5-foot-11, 184 pounds, said he sees it every year. Coaches want to experiment in camp. They put Shields through the ringer and demanded that he first put some pop in his tackle. The coverage stuff was important but he had to answer: Could he hit?
"And he showed that," said Williams. "He was focusing more on his physicality at that point and he's gotten that part of his game good."
Shields was playing well enough to start the 2012 season but against Houston Oct. 14, he suffered shin, knee and, more seriously, ankle injuries. He missed six games and seven weeks of work. He couldn't even walk at first because of the pain. He said the only way to return from that injury was to make sure he had his famous speed back.
Three weeks ago, it was. He shut down a reverse by the Detroit Lions, caught an interception and had a shot at two more. He says he feels no ill effects of the injury at all.
That's clear. He stuck to the hips of Tennessee wideout Kenny Britt like the cream cheese frosting of a Christmas carrot cake.
And two games ago at Chicago, when push came to shove, Shields shoved back. Guarding 6-3 WR Alshon Jeffery, who was targeted four times, Shields didn't allow a single completion.
"Sam did a great job on him," said Hayward. "I'm not sure he got open all that much."
But Shields also tapped into that physical training from camp as soon as he was shoved to the ground by Jeffery in the end zone of Soldier Field. Mr. Nice Guy looked mad as you-know-what. He played that way. Shields also got a few pass interference calls go his way - on the offense for once. But he said that wasn't just luck.
"While we watch film, we see guys on other teams get grabbed and pushed, and we're like, why don't they call that?" said Shields. "So we're always fighting for that call. Even during training camp when the officials come to practice, we ask why. Sometimes they don't see it. We study guys that push and grab. Most of the times it's the big receivers that push and grab."
Shields is the lightest player on the roster, 8 pounds under the next lightest, Randall Cobb and Hayward. He hasn't gained an ounce since his rookie season. He loves to train in the off-season by running. He's built for basketball, a point guard on a football field.
But he's making the most of what he has by adding physical tackling to his already legendary speed.