SANTA CLARA There's one question running through Scott Tolzien's mind this week: What would Matthew do?
Matthew is Lions quarterback Matthew Stafford, and Tolzien's assignment as the 49ers' scout-team quarterback is to give his defensive teammates the best rendition possible of that week's opposing passer, down to every quirk, tendency and tell.
It's a role for which Tolzien and his fellow scout-team performers received rave reviews last week.
Cornerback Carlos Rogers said he and his fellow defenders had no surprises from Aaron Rodgers and the Packers on Sunday, and for that he credited defensive coordinator Vic Fangio and the scout-team offense.
"Everything we see out there on Sunday, we see during the week," Rogers said. "(Fangio) did a good job of preparing us. Most importantly, that scout team did a good job of giving us some looks that Green Bay was going to do, and it made it much easier out there on Sunday."
Tolzien's supporting cast mostly includes players on the practice squad.
Wide receiver Nathan Palmer, for example, played the role of Packers wideout Greg Jennings. Even Michael Thomas, a safety, stepped in and played one of the Green Bay wideouts, Randall Cobb.
There were some prominent names involved as well.
Neither first-round draft pick A.J. Jenkins nor second-round pick LaMichael James played against the Packers. But both were integral in preparing for them.
During practice, Jenkins lined up as Rodgers' favorite target from 2011, Jordy Nelson. This week, Jenkins has an even bigger assignment. He's tasked with giving the defensive backs a taste of Lions wide receiver Calvin Johnson, who is five inches taller and at least 40 pounds heavier than Jenkins and who led the NFL in receiving yards last season.
"They want me to go up after the ball," Jenkins said of requests by the defensive backs. "When the ball's in the air, just go up and get it."
Coach Jim Harbaugh is careful never to use the term "practice squad" or "scout team." Instead, he calls it "the developmental squad" because he hopes the young players on those units turn into his "future starters." Their day-to-day role, however, is more practical.
"I think that's where it all starts, I really do," Harbaugh said. "Any three-and-out that you get in the game, I believe, first starts on the practice field with the guys that are demonstrating the opponents' offense. Or any big play that you get on offense, it first starts with the men that are demonstrating the defense."
While preparing for the Packers, Tolzien picked up on Rodgers' cadence. The Packers quarterback, after all, does a good job at baiting defenders into crossing the line of scrimmage before the snap.
Tolzien also noted that when Rodgers scrambles, he likes to do so in the direction opposite of where his receivers are running. Why? Because there are fewer defenders on that side of the field.
Stafford, meanwhile, prefers to stay in the pocket.
"But he'll take chances," Tolzien said. "He's got an unbelievable arm, and he's not afraid to showcase it. And then it's pretty simple. When he's got Calvin Johnson one on one, that's who he's going to. And I try to see the same things he sees what would Matt Stafford do here? If it's one on one with Calvin Johnson, you're probably going to throw him the ball."
Johnson missed Wednesday's practice with the Lions because of a foot injury. However, he remains the 49ers' defensive focus heading into Sunday night's game.
"He's the featured guy," cornerback Tarell Brown said. "Everybody knows that. The thing for us is to play our style of football. Go out there and try to be physical. Go out and there and get our hands on him. Try to slow that guy down. He's going to make catches, but you want to limit his yards after the catch. And go out there and compete with him for every jump ball."