THERE ARE NO guarantees in sports–and no gimme games. Because talent is only part of what it takes to win, upsets are always possible. If they weren’t, most of your favorite sports movies wouldn’t have been made.

We learned this long ago. Our teachers were the U.S. hockey team in the 1980 Winter Olympics, and the Super Bowl champion New York Jets in 1969.

There were the 1985 Villanova Wildcats, who stunned the defending champion Georgetown Hoyas in the NCAA men’s basketball finals. And Buster Douglas, a 42-1 underdog who knocked out Mike Tyson.

No matter how lopsided a matchup looks on paper, counting out a team (or an athlete) is a mistake.

The Arizona Cardinals are not David. And at 3-2, the Washington Redskins certainly aren’t Goliath. But it would be easy for a fan–or a Redskins player–to look at Arizona as an inferior team.

The Cardinals enter today’s game at FedEx Field a week removed from a 15-point whipping by the Carolina Panthers and their 43-year-old quarterback, Vinny Testaverde, who beat Arizona less than a week after he was signed off the streets.

As silly as Carolina’s quarterback situation was last week, Arizona’s is indisputably worse. The Cardinals lost starter Matt Leinart for the season with a collarbone injury just two weeks ago.

Leinart’s mentor-turned-replacement, Kurt Warner, injured his left elbow last weekend. His status for today’s game isn’t certain, but even if he starts he won’t be at his best.

It’s likely that we’ll see his backup, Tim Rattay, at some point today. Two weeks ago, Rattay was watching games on his couch like you and me.

In his debut last Sunday, Rattay was intercepted once for every four passes he completed. He’s had a week to learn Arizona’s offensive-scheme, and should look more comfortable because of that on Sunday.

Whether Rattay has a week or a year to study his playbook, though, he’s not going to scare defenses. Neither should 36-year-old Warner, at less than 100 percent. The opposite of being fearful is being confident, and Washington’s defense is certainly that.

But Leinart’s absence–and the fact that the Cardinals’ defense isn’t in the league’s top half against either the run or the pass–should scare Washington.

That’s right, the Cardinals’ overall mediocrity is what makes them frightening.

Call me crazy, but I think the fact that Leinart will be on the sideline and somebody not as talented will be in the huddle should be disconcerting for a Redskins team that’s a week away from playing the unbeaten New England Patriots.

I’d like to think that I’m crazy, but professors Douglas and Villanova tell me different. One thing Washington has going for itself today, though, is that the Redskins benefited from the same lessons we did.