When Bill Polian was general manager of the Buffalo Bills in the early 1990s, he would go to training camp knowing his team would be one of the top half-dozen in NFL.

This year, as president of the Indianapolis Colts, Polian considers his team one of the best 19 in the league. In the salary-cap era, he figures that makes them Super Bowl contenders.

“I look at maybe 11 teams in the AFC and eight in the NFC and can visualize any of them getting to the Super Bowl — with a big ‘if,'” he says. “The right bounces and good health. If we lose any one of five guys, we’re in deep trouble.”

Polian isn’t the only optimist as NFL training camps open in the next 10 days. Even the dismal Cincinnati Bengals have hope that new coach Marvin Lewis can get them to .500 for the first time since 1996.

The best teams are more cautious than the lesser ones.

“A lot of luck plays into winning a championship — sometimes just a matter of inches or feet,” said Rich McKay, general manager of Tampa Bay, which won its first title last season.

“We’re not going in saying we’ll win the Super Bowl again. We focus on winning our division. Then we try to get home-field advantage. And then we hope for luck.

“Last year, we finally got some.”

The past five seasons prove that when the stars are aligned right, almost anyone can win.

The Rams and Titans went to the Super Bowl five seasons ago after being a combined 12-20 the previous year; the Giants and Ravens came from nowhere to get there after that.

One player, second-year QB Michael Vick, turned Atlanta into a playoff team last year and is largely responsible for this year’s sellout at the Georgia Dome, which until his arrival was often half empty.

Last year, a quarter of the 256 games were decided by three points or fewer, and there were a record 25 overtimes.

That’s where luck comes in, typified by an opening-day contest in which Cleveland’s Dwayne Rudd tossed his helmet to celebrate what he thought was a victory over Kansas City and was penalized, allowing the Chiefs to kick a winning field goal after time had expired.

Even Tampa Bay was considered a second-tier contender a year ago.

Sure the Bucs were regular playoff participants, but they were coming off a turbulent offseason. “It was 10 days of turmoil,” said McKay, who almost departed himself when the Glazer family, the team’s owners, kept overruling him on coaching and other decisions.

But none of that mattered when the games began. The defense was more dominant than ever, and new coach Jon Gruden made the offense respectable after coming from Oakland after the firing of Tony Dungy and the abortive efforts to hire Bill Parcells and Steve Mariucci.

Mariucci was fired by the 49ers despite a 57-39 record in six years. He immediately was hired by Detroit, giving the Lions hope after five victories in two seasons under Marty Mornhinweg.

As for Parcells, he’s in Dallas in an unlikely alliance with Jerry Jones, the most hands-on owner west of Washington’s Dan Snyder.

Few contenders can afford to lose their quarterback — if Peyton Manning gets seriously hurt, the Colts’ season would be over (Brock Huard is his backup.) It’s also unlikely that A.J. Feeley could rescue the Eagles again if Donovan McNabb goes down.

Still, the league is quirky enough that an unknown NFL Europe and Arena League refugee named Kurt Warner was able to step in for Trent Green in 1999 and lead the Rams to a title. And a sixth-round draft pick named Tom Brady did the same when Drew Bledsoe was injured two seasons later.

This year, Warner is a major question mark.

Last season, he injured a hand and arm and was 1-6 as a starter as the Rams fell from 14-2 to 7-9. Their status as a contender this year depends on his comeback (and Marshall Faulk’s) from injuries.