Most of football’s most hallowed clichés have to do with defense being the most important part of the game : “Offense sells tickets, defense wins championships,” et al.

If that’s true, then why is Indianapolis Colts’ safety Bob Sanders merely the Associated Press 2007 NFL Defensive Player of the Year, as announced yesterday, instead of the NFL’s MVP, which was awarded to New England Patriots quarterback Tom Brady?

We all know the reason, of course. Offensive players have an enormous advantage over their defensive counterparts when it comes to recognition: flashy stats. No one knows exactly what to make of defensive statistics, and even if they did, skilled position players have a second advantage over the guys on the other side of the ball: They call their own number or have it called by someone else as often as the head coach wants. Great defensive players, on the other hand, are the guys you try to run or throw away from. Sometimes the best defensive player on the field will be the guy with the least impressive stats – you have to look for his real effect elsewhere.

The Colts’ free (and sometimes strong, depending on where defensive coordinator Ron Meeks wants him to line up) safety Bob Sanders, the current NFL defensive player who most resembles Ronnie Lott in terms of impact, has pretty good stats. He has 96 tackles — 71 solo and 25 assisted. That sounds good when you say it, but it doesn’t knock you over until you examine it carefully. The top 30 players in the league in terms of total tackles are linebackers, which is the way it’s supposed to be. (As Bear Bryant put it, “the defensive linemen up front aren’t supposed to make the tackles, they’re supposed to open things up so the linebackers can make ’em.”) Of the next 12 players in total tackles, there are three non-linebackers, San Francisco’s Michael Lewis with 104, and Carolina’s Chris Harris and Cleveland’s Sean Jones, both, like Sanders, with 96. All are safeties.

We know that all four of those players must be good tacklers because you don’t get around 100 tackles without being a good tackler. What we don’t know is if their tackles had as much impact on games as Sanders’s did. Almost certainly not: San Francisco, Carolina, and Cleveland all had lousy defenses this year, which is one of the reasons that their secondaries were making so many tackles. (Bear Bryant, again: “You know you’re in trouble when the guys making the most tackles for you are in your defensive backfield.”) The defense Sanders plays for, on the other hand, is one of the best in the league. The Colts were third in yards allowed per game, 279.7, just 13.3 behind the number one Pittsburgh Steelers, and the Colts might have finished number one if their final game against Tennessee wasn’t a meaningless one in which the regulars sat out the second half.

This makes it absolutely astonishing that Bob Sanders got in on so many tackles. In terms of effectiveness against the run, it was as if the Colts had an extra linebacker in on nearly every down.

Sanders also had 3 1/2 sacks on safety blitzes and two interceptions. I don’t know why he didn’t have more than just two interceptions, though opposing quarterbacks, when they could, chose to throw where they thought Sanders was not. In any event, Sanders, who could be observed several times a game separating receivers from the ball — and often from their helmets — anchored the best pass defense in the league. The Colts were second in yards per throw allowed at 5.88 (the Steelers were first at 5.72) and second in yards allowed passing per game, 172.8. Tampa Bay was first at 170.5, but the Bucs played in the soft NFC and did not have to face, as the Colts did, Tom Brady and New England.

Football analysts have spent a lot of fruitless time over the years arguing about whether the top defensive player should be chosen from a team with a good defense or a bad one. The question really can’t be answered with any certainty. If you rule out players from bad teams, you exclude legendary linebackers like the Detroit Lions’ Joe Schmidt and the Chicago Bears’ Dick Butkus, who were regarded as two of the best players in the game by those who watched them every day. But there’s no reason to disregard players on great defenses just because they are surrounded by talented teammates — especially when a particular player has clearly made the most impact.

The best players on the Colts’ defense were, by consensus, defensive end Dwight Freeney and Sanders, but when Freeney went out with an injury in Indy’s ninth game of the season, the defense didn’t slip a notch. In fact, the Colts won their next six games before the insignificant loss to the Titans on the last day. On the other hand, from 2005 through 2006 Indianapolis was 21–3 when Sanders was in the lineup and 10–4 when he was not. The players and coaching staff were adamant in their claims that Sanders return to the lineup after a knee injury boosted the sagging Colts through the end of the 2006 season and the Super Bowl.

Indianapolis goes into the playoffs with an offense that was fifth in the league in yards per game. Their defense, in comparison, was second in yards per game allowed, and probably the best overall in the league. It’s arguable, then, that Bob Sanders is the most important player on the team, and as such has a legitimate claim not only on defensive player of the year but on the NFL’s MVP award.

Mr. Barra is the author of “The Last Coach: A Life of Paul ‘Bear’ Bryant.”