Case Keenum received a text message from Hall of Fame quarterback Kurt Warner this past week. Keenum preferred to keep the details private, but the motivation behind Warner's message should be fairly obvious.

Keenum became one the best stories in the NFL this season. His performance in place of Sam Bradford etched a spot in Vikings lore. Warner owns a gold jacket because he knows a thing or two about producing out-of-nowhere success.

He also can explain the difference between regular-season pressure and playoff pressure, a journey of discovery that Keenum will embark upon Sunday with his playoff debut against the New Orleans Saints.

Keenum's lack of postseason experience became a natural story line. Despite stretches of superb play in a career season, Keenum doesn't have a playoff track record and unknowns tend to make people uneasy.

That doesn't guarantee any outcome, good, bad or in between. It just means nobody knows for sure how Keenum will handle the magnitude of a win-or-go-home edict.

Experience is ideal in any profession, obviously, because it gives a certain comfort level. Drew Brees will start his 13th career playoff game Sunday. He owns a Super Bowl ring and understands what playoff intensity and pressure feel like.

But to assume Keenum can't or won't continue to perform the way he has all season is purely a guess, nothing more. Just as it is to assume that Brees won't make mistakes because he has been on this stage many times.

Keenum's demeanor hasn't changed since the day he took control of the offense. He comes across as meticulous about preparation but also unafraid to play loose. He's part gunslinger, part bookworm. He seems completely in tune with Pat Shurmur's scheme and his personnel.

"I'm not looking too much at the big picture," he said. "I'm keeping my blinders on and thinking about what's going on right now."

One popular opinion floated in assessing Keenum's inexperience is a call for Shurmur to take a more conservative approach to lessen the potential for disaster. The theory being, the Vikings have a historically stout defense. Just don't do anything offensively to screw it up.That's a slippery slope as a strategy. There's a big difference between being careful and playing scared. Keenum must avoid taking unnecessary risks, but he also has to be himself and feel free to make those off-script plays that contributed to his success.

"I'm going to play like I know how to play," he said. "I don't have to be anybody but myself. More conservative or less conservative, either way I'm going to be me."

Mike Zimmer refers to Keenum's personality as "excitable." He also reiterated that he's particularly fond of Keenum's competitive guts, to paraphrase.

"He's pretty much charged up all of the time," Zimmer said.

That's gotten Keenum in trouble a few times with interceptions, but his gumption also has turned many sacks or busted plays into something positive. Walking that line in the playoffs carries added importance.

"I'm always working on my decision-making," he said.

Keenum finished second to Brees in completion percentage among full-time starters, coupled with only seven interceptions, so his decision-making was largely on point. A continuation of that will be critical because the Saints defense finished in the top 10 in takeaways.

"We've got to be smart with the football," Keenum said.

Smart but not overly cautious. They have to trust that Keenum will continue to strike the right balance between playing aggressive and taking care of the ball.

No doubt his emotions will be rip-roaring. He described the adrenaline he feels waiting in the stadium tunnel before games as "not a scared nervous but an excited nervous."

Everything will be magnified in his playoff debut, the biggest moment of his career. The way he performed this season gives confidence that he can be the organization's quarterback moving forward. Some might disagree, wanting to see how Keenum performs in the playoffs.

No postseason experience creates unknowns, maybe even anxiety for some fans. The Vikings just need Keenum to be himself, play like he has all season. That should be good enough.

Chip Scoggins chip.scoggins@startribune.com