GREEN BAY, Wis. -- James Starks had 18 carries for 73 yards against the San Francisco 49ers and his coaches didn't cite him for any major mistakes in pass protection. He even remembered to thank his offensive linemen.

Not bad for a rookie who hadn't played a meaningful down in nearly two years.

"The kid, he never gave the impression that it was too big for him," Packers running backs coach Edgar Bennett said. "He was poised, I guess you could say. Even in pregame warmups, you saw it in his eyes. This kid was ready to play."

He certainly had plenty of time to get ready before.

Starks missed his entire senior season at Buffalo because of a shoulder injury and slipped to the sixth round of the draft before the Packers chose him.

Then he hurt his hamstring in offseason workouts and began the season on the physically unable to perform list. Green Bay added him to the active roster Nov. 9 but he didn't get into a game until Sunday.

"Even when I was out, I was in the playbook a lot more than probably the other guys," Starks said. "They were probably tired and drained out. I had a little extra time to study the playbook and get in there and learn concepts a lot more. I feel like I'm pretty much catching up. It doesn't feel like I'm far behind at all."

Coaches believe Starks has far more to show, and are eager to see his speed.

"When he comes off the back end, you better watch out," Packers coach Mike McCarthy said. "It's going to the end zone."

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Bennett insists the 6-2, 218-pound Starks runs a sub-4.4-second 40-yard dash and can be a breakaway threat.

"Oh yeah," Bennett said. "He has that type of ability."

Bennett praised Starks for using his time away from football to prepare.

"This kid was coming in here early and leaving late, studying film and making sure he was raring to go," Bennett said. "Like I said, it was about making the most of his opportunity. And he was excited to get out there and play with his teammates. He kept talking about going down and complimenting the offensive line for the job they were doing, I mean, when you see a young kid that in tune, making sure that he thanked his teammates, that's what it's all about."

Quarterback Aaron Rodgers -- who hasn't been afraid to get after teammates for their mental mistakes of late -- made it clear he wants to see more out of Starks and other younger players in practice.

"Say what you want about Ryan Grant. Obviously, I think he's a lot more appreciated in injury than in health, unfortunately," Rodgers said. "That guy, no one could ever question his practice habits. Look at Donald Driver, Greg Jennings, Jordy Nelson, Brett Swain. Those guys practice as well as everybody. Every day they bring it. Jermichael (Finley) became that player this season. I want to see those young guys take that seriously.

"Because how can I have any confidence in you being on the field if you can't show me what you can do in practice? That to me, is the most important thing. And that's what being a professional is about. This is a whole-week job."

The fact that Starks' debut was such a big deal in Green Bay this week shows just how badly the Packers running game is struggling going into Sunday's game at Detroit.

Green Bay has had a pass-first offense under McCarthy, and that certainly hasn't changed after a season-ending ankle injury to Grant in Week 1. Rodgers was their leading rusher in a loss at Atlanta two weeks ago.

Brandon Jackson has struggled, and has made the case in recent weeks that he needs more carries to get into a rhythm. That isn't likely to happen if Starks can show that his debut wasn't a fluke.

"I would like to have some type of rotation of all three of those backs, but Brandon is still our main guy," McCarthy said. "He's done it all year. As I've stated before, I don't think it's in our best interests with as much football as we have in front of us to sit there and run Brandon Jackson 25 times a game."

Jackson didn't complain about getting only four carries to Starks' 18 on Sunday.

"He just adds another dimension," Jackson said. "Hopefully, he's going to do good things in the running game to help push us forward."

Starks said he'll take whatever the coaches are willing to give him.

"We've got great backs," Starks said. "Whatever is asked of me, that's what I'm going to do. I'm up for any challenge, just as the other backs are. If you put us in the right situation, we'll all succeed."