GREEN BAY — Green Bay's Aaron Rodgers and Dallas' Tony Romo come from opposite ends of the football universe.

Rodgers was drafted in the first round, Romo went undrafted. Rodgers played in the Pac-10 Conference, Romo in Division I-AA. Rodgers replaced Brett Favre, Romo plays like Brett Favre.

For all their differences, however, the quarterbacks whose 2-0 teams will meet in an NFC showdown Sunday night at Lambeau Field share one common trait: They were forced to sit and watch for a while before getting their chance to start in the NFL.

The league maxim is quarterbacks who serve apprenticeships have a greater chance for success than those who are thrust into starting roles as rookies.

Great expectations and huge contracts often don't allow teams to exhibit patience these days, but Rodgers and Romo are proof it's best not to throw a quarterback into the fray until he's had at least one season to figure out what it takes to play the position in the NFL.

Romo has been to the Pro Bowl in each of his two years as Dallas' starter and Rodgers has been outstanding in his first two games as Favre's successor in Green Bay.

Still, competitive instincts often overrule common sense and neither one was thrilled about sitting on the bench for three seasons before becoming the starter.

"Would I have played well in the first year? Probably not, to be honest," Rodgers said. "I really felt like the second year I started to get it, but the third year I had it down."

Rodgers and Romo are completing at least 70 percent of their passes this season and are ranked in the top seven in the NFL in passer rating.

"I felt like after about my first season I really had a grasp of things that were going on," Romo said. "You're going to find new things every time you play, but I feel like the mental side of it, after the first year, you really should make a big improvement in that. I'm under the impression (a team should) always make a guy wait a year and then go from there."

Of course, a quarterback's success in the NFL is tied to many things: the talent, intelligence, durability and background of the player; the quality of coaching he gets; the strength of the team when he takes over.

But given the vast potential for damage to the psyches of young quarterbacks, a little learning time clearly goes a long way.

For every Peyton Manning and Ben Roethlisberger who were instant successes, there are many big-name quarterbacks who failed.

David Carr, Joey Harrington, Tim Couch, Ryan Leaf, Heath Shuler and Rick Mirer were huge busts after starting as rookies. Vince Young, Matt Leinart and Alex Smith are headed down the same path.

There were busts among those who waited until their second year to start — Akili Smith comes to mind — but Tom Brady, Drew Brees, Carson Palmer and Philip Rivers offer compelling evidence that sitting and watching for a season or two is beneficial.

Rodgers and Romo feel they could have played sooner than they did, but at least they were given a fighting chance to succeed by their teams or their circumstances.

Contact Tom Oates at toates@madison.com or 608-252-6172.