Mike McCarthy has a chance for a redo.

On Sept. 9, 2012, the Green Bay Packers hosted the San Francisco 49ers in the season opener at Lambeau Field and McCarthy was set to spring multi-functional offensive game-breaker Randall Cobb on an unsuspecting 49ers defense.

Still a little bit of an unknown professionally, Cobb had a history of lining up at receiver, running back and quarterback at Kentucky. McCarthy had given training camp visitors a glimpse of what Cobb might be able to do out of the backfield, but he had hoped the 49ers wouldn't be prepared for him.

It turned out they were. As soon as Cobb broke the huddle and lined up at halfback or motioned into the position, they adjusted their defense. McCarthy later said he felt it was media reports that tipped off the 49ers about Cobb's new role (although they undoubtedly noticed some plays he ran from there the year before).

It is now 2014 and McCarthy and his staff are preparing for their fourth meeting in two years with the 49ers. This time around Cobb's role may be a true mystery because other than the 37 snaps he had against Chicago on Sunday — mostly as a slot receiver — there is a 10-game empty canvas for the 49ers to contemplate.

Cobb missed all that time with a broken leg suffered against Baltimore in Week 6 and in his absence the Packers shifted their offensive emphasis more toward running the ball. Behind rookie Eddie Lacy and his franchise rookie record 1,178 rushing yards and 11 touchdowns, they became far less one-dimensional.

After catching two touchdown passes in limited playing time against the Bears, Cobb is the Packers' mystery man heading into their playoff opener against the 49ers on Sunday at Lambeau Field.

"Randall does so much for our offense," quarterback Aaron Rodgers said Wednesday. "When he was out though, one good thing I think that came out of that though was (receiver) Jarrett Boykin's emergence. He really stepped up and made some big plays for us and proved his value to this offense. And also we got to move Jordy (Nelson) inside and he got to show his versatility inside.

"So, bringing Randall back with the way those guys can be interchangeable at different positions definitely has a lot to offer."

McCarthy and his coaches are taking extra time this week to prepare for the 49ers, and while Cobb's role Sunday certainly isn't the only reason it makes sense that Xs and Os are being drawn all over the place to figure out ways for Cobb to be a factor.

Two weeks ago, the Packers weren't even sure Cobb would be ready for this game, but he made so much progress last week he was given the green light to play in the division-decider against the Bears. Set to play maybe a dozen or so plays, Cobb wound up with triple that and won the game with a 48-yard touchdown catch with 38 seconds left.