Joe Berger has no idea what a grade of 26.8 actually means. But he's a polite guy, so he thanked Pro Football Focus for crunching its analytics thingamabob and spitting him out as the best center in the NFL this season.

"Any time anyone recognizes you as doing well at something, you know, it's good," said Berger, whose first NFL playoff start in an 11-year career will come Sunday when the Vikings play Seattle in an NFC wild-card game at TCF Bank Stadium.

Berger, who edged Cowboys Pro Bowler Travis Frederick (25.4), admits he's skeptical and hasn't followed the website closely.

"Until most recently, I guess," he said. "I heard my name kind of get thrown out there with it."

See, not every PFF grade is meant to bludgeon a struggling player and trigger entertaining exchanges between old-school coaches and new-school reporters. In fact, in a league of 1,696 active players, Berger's point total was surpassed by only 57 players (3.4 percent).

Take that, Adrian Peterson, the NFL rushing leader, who ranks 36th among running backs with a 2.6 point total.

Joe Berger sees room to improve. “There are things you wish you could have done better, especially from the center’s perspective,” he said.

"As far as how they get their scores and that stuff, I don't know how all that comes about," Berger said. "I know you hear mixed reviews on it. It's a cool number, but what matters most to me is how I'm graded in our room."

In that room, Berger also ranks highest among all linemen. The specifics aren't public knowledge, but they support the decision by General Manager Rick Spielman to make re-signing the then-backup Berger a priority in free agency. Once center John Sullivan's back gave out in August, it became possibly the greatest quiet move made by a playoff team this season.

The Vikings still don't have a great offensive line. It's inconsistent, rising to good on its best days. But it also didn't prevent the Vikings from winning 11 games and punching the Packers off their longtime perch atop the NFC North.

"I think they've improved," coach Mike Zimmer said. "They still have a lot of work to do. We're not where I would like to be. But one thing that they have done really well is they've battled. They have fought and competed. But we can do better."

To better appreciate where the offensive line is, look where it started.

Sullivan and right tackle Phil Loadholt were lost to injuries before the season. Right guard Mike Harris had one career start at guard. Left guard Brandon Fusco moved from right guard. And left tackle Matt Kalil was coming off a season wrecked by bum knees.

Rookie T.J. Clemmings wasn't ready to start in September, but he started all 16 games at right tackle. Berger, a career utility man at the three interior line positions, started all 16 games for the first time at age 33. Kalil, Fusco and Harris also started all 16 games.

"We have been inconsistent, you could say," Berger said. "I think we have some young guys that needed to learn just how to play the game. But I think we have a group of guys that try to get better each week. And I think we have done that."

Sunday, the Vikings face a roster filled with players who have played in the past two Super Bowls. The Vikings counter with a 53-man roster that has only 23 players with playoff experience. Berger's only playoff participation came on special teams when the Vikings lost a wild-card game at Green Bay during the 2012 season.

Only 11 Vikings have started a playoff game. Of those 11, only nose tackle Linval Joseph and wide receiver Mike Wallace have started or played in a Super Bowl. And Joseph has missed four of the past five games because of a toe injury.

Speaking of Joseph, he's the only Viking with a PFF point total (38.3) higher than Berger's. But Berger's number is high enough that he might be the first player to question whether his rating is too high.

"When you look back, there are things you wish you could have done better, especially from the center's perspective," Berger said. "I take a lot of mistakes on my own shoulders as far as maybe I could have communicated things better to get everybody on the same page.

"Maybe some of the mistakes that some of the other four linemen were having wouldn't have shown up if I had communicated better. That's the kind of stuff that doesn't show up on Pro Football Focus."

Mark Craig • mcraig@startribune.com