It happened to him 26 years ago, but Randall Cunningham still remembers what it felt like on game day as an NFL rookie replacing a 13-year veteran as the starting quarterback.

"I almost pooped myself," said Cunningham, who replaced Ron Jaworski as the Philadelphia Eagles' starting quarterback in Week 2 of the 1985 season.

"I was bright-eyed and bushy-tailed, a high draft pick [second round], and I could make things happen with my feet. But was I ready to start in the NFL? No way. I took eight cans of film home every night to watch. But so many things happened in that game that I wasn't used to in college."

Cunningham went 14-for-34 with four interceptions, no touchdowns and a 22.7 passer rating in a 17-6 loss to the Los Angeles Rams.

Sunday, the latest bright-eyed and bushy-tailed rookie will make his NFL starting debut when Vikings first-round draft pick Christian Ponder replaces another 13-year veteran, Donovan McNabb.

"Who are they playing?" Cunningham asked.

The Green Bay Packers.

"Talk about being thrown into the fire," said Cunningham, who also played for the Vikings. "Wow."

You got that right.

The defending Super Bowl champion Packers bring the league's only unbeaten record and one of its more exotic defenses to face the Vikings.

The Packers lead the league in scoring and are tied for seventh in points allowed.

Ponder doesn't sound overwhelmed by it all. Or at least he didn't before kickoff.

"There will be some growing pains and some steps that you have to go through, but I'm looking to have success," said Ponder, who completed nine of 17 passes for 99 yards in relief of McNabb in last week's 39-10 loss at Chicago. "I'm not really thinking about what I'm concerned about."

Ponder and coach Leslie Frazier are expecting a heavy dose of blitz packages, but Packers defensive coordinator Dom Capers is one of the more creative defensive strategists in the game. He will use anywhere from one to five defensive linemen, two to four linebackers and three to six defensive backs.

Pressure can come from anywhere and everywhere. Or nowhere, as Capers could show blitz and then drop players into coverage. According to ESPN Stats & Information, Capers blitzed the past three rookie quarterbacks he faced -- Tampa Bay's Josh Freeman and Detroit's Matthew Stafford in 2009, and Carolina's Cam Newton earlier is year -- 30.7 percent of the time, compared to 36.7 percent of the time against veterans.

"Every game is different," Capers told reporters in Green Bay this week.

Learning to drive

Vikings fans are hoping Ponder duplicates what Freeman was able to pull off in 2009. Making his NFL starting debut, Freeman had three touchdown passes, no interceptions and an 86.1 passer rating in a 38-28 upset over a Packers team that was heavily favored to win on the road against a 0-7 team.

Success or failure in a quarterback's rookie starting debut is as unpredictable as the league itself. Expectations, however, were changed for years to come in 2008 when Atlanta's Matt Ryan and Baltimore's Joe Flacco started from Day 1 and led their teams to the playoffs. In Ryan's debut, he completed nine of 13 passes for 161 yards, one touchdown, no interceptions and a 137.0 passer rating in a 34-21 victory over Detroit. The touchdown -- a 62-yarder on his first pass attempt -- went to current Vikings receiver Michael Jenkins.

"It's too early to make comparisons between Matt and Christian," Jenkins said. "We went 11-5 that year. Matt had the whole offseason, all the OTAs, all the minicamps to learn the system. That helped him come in and excel from Day 1."

Ponder didn't have any of that because of the NFL's 4 1/2-month lockout. He comes in with the reputation of being an intelligent quarterback with mobility, speed and what offensive coordinator Bill Musgrave calls a "sixth sense" for knowing precisely when to take off to avoid pressure.

But, even so, most rookie quarterbacks begin the NFL journey like a lost child at the Mall of America.

"The best way I can describe being a rookie quarterback is to remember back to when you first got your driver's license when you were 16," said former Vikings quarterback and 2002 NFL MVP Rich Gannon. "When you get behind the wheel that first time, all you see is the car in front of you. As you get more experienced, you see the car in front of you, the four cars ahead of that one, the oncoming traffic, the pedestrian off to the side, the traffic behind you. You see and sense things that you never even imagined the first time."

Mixed results

Hall of Famer Troy Aikman, a No. 1 overall pick, was among the dazed and confused in his first rookie start. He threw two interceptions, no touchdowns and posted a 40.2 passer rating in a 28-0 loss to the Saints in 1989. Peyton Manning, another No. 1 pick, threw three interceptions, one touchdown and had a 58.6 rating in a 24-15 loss to Miami in 1998.

Then again, current Bengals rookie Andy Dalton, a second-round draft pick, completed 66.7 percent of his passes with a touchdown, no interceptions and a 102.4 passer rating in a 27-17 victory at Cleveland in Week 1. He's now 4-2 on a team that won four games a year ago.

"I never felt that the challenge was getting the rookie ready to play," said Packers coach Mike McCarthy, who was offensive coordinator in San Francisco when the 49ers drafted Alex Smith No. 1 overall in 2005.

"It was really how he fit into the team as far as was the team ready for him to play. I don't think it's realistic to go out and ask your rookie quarterback who is playing in his first game to make all the throws and carry the whole offense. You can't go and just be conservative either ... but I think you have to have a happy medium in there where he can play his game but you don't put all the stress on him to be the No. 1 priority."

McCarthy said he learned that the hard way with Smith. In a 28-3 loss at home to the Colts, Smith completed nine of 23 passes (39.1) for 74 yards, no touchdowns and four interceptions.

"There was a difference of opinion on how we were going to play the game," McCarthy said. "In hindsight, our defense played extremely well against the Colts that day and we played probably too wide open on offense. We put too much on the quarterback. I regret the game that I called that day. I felt like I put Alex in some tough spots."

Waiting your turn

Packers quarterback Aaron Rodgers has become the example for those who argue it's better for quarterbacks to sit and learn for a few years. He sat behind Brett Favre for three years before starting his first game in 2008.

"I could have played as a rookie, but I don't know about being successful," he said on his weekly radio show. "It's tough when you're in a situation where the expectations on your shoulders are far greater than the potential in your locker room. One person has never won a game in this league."

For what it's worth, the Vikings have assistants who coached two quarterbacks to NFL Offensive Rookie of the Year honors the past six seasons. Quarterbacks coach Craig Johnson was with Vince Young in Tennessee in 2006, and Musgrave was with Ryan in 2008.

Johnson talked about the inevitable "storm" that all confused rookies must weather.

"I'm not being negative because that's what happens," Johnson said. "There is going to be a storm. And when that storm comes, more than anything, [it's important] not to be, 'Oh, man, life it going bad,' my shoulders are drooping, I got my confidence knocked out. That's what [Ponder] has to get ready to do."

Of course, that's easier said than done when the stomach is in knots, the opposing quarterback is the reigning Super Bowl MVP and one is facing a defensive coordinator in his 26th NFL season.

"Where is the game being played?" Cunningham asked.

Metrodome.

"Whew," Cunningham said. "At least he's got that going for him. But, wow, does he have to grow up quick against that team, or what?"