JACKSONVILLE, Fla. -- Patriots linebacker Don Davis has looked into his crystal ball and seen the future. After starting the season as a backup linebacker and logging considerable playing time at safety, Davis sees pro football in a different light now, a light turned on by the genius of Bill Belichick.
"I guarantee 20 years from now, there will be one of the photos, like how you have the whole Mike Holmgren coaching tree; you'll see a Coach Belichick New England Patriots tree sometime in the future," Davis said. "You will definitely see a Mike Vrabel, possibly a Willie McGinest, Rosevelt Colvin, Rodney Harrison, Troy Brown, Tom Brady."
But Super Bowl XXXIX is now, and Davis keeps telling the younger players to never forget what occurred with the Patriots. The Red Sox might have ended the Babe Ruth curse, but the Patriots made a repeat trip to the Super Bowl with the most improbable lineup of pass defenders in NFL history. Davis was a linebacker playing safety. Brown was a wide receiver playing slot cornerback. Randall Gay was an undrafted rookie starting at cornerback. Eugene Wilson, a former second-rounder drafted at cornerback, is starting at free safety.
Supposedly, the Patriots' secondary operated all season with their main secondary hands "Ty-ed" behind their backs. Ty Law and Tyrone Poole, the two cornerbacks who helped the Patriots win last year's Super Bowl, missed a combined 20 games because of injuries, were non-factors in the second half of the season and were placed on injured reserve.
Fortunately, the Patriots' smart coaching staff looked into their crystal balls and had the foresight to begin contingency plans before injuries hit. At the start of training camp, Brown experimented as a slot cornerback. One of the Patriots' smarter players, Brown looked good enough at corner that the thought of using him later was filed away.
Three weeks into the preseason, secondary coach Eric Mangini posted a note for Davis to see him in his office. "When you see a sign like that, nothing is good about that," Davis thought. Davis arrived in his office and couldn't believe the words.
"How would you feel about playing safety?" Mangini asked.
"You're trying to get rid of me, man?" Davis responded.
"No, this is something we've been kicking around, and we really think you can do it," Mangini said.
Davis, a backup linebacker and special teams player, thought about it for a second. The team was overloaded at linebacker so playing time would be minimal there. Rookie safety Guss Scott was hurt and destined for injured reserve, so the team was thin at safety. With speed and good instincts, Davis tried it and liked it. Pretty soon, coaches started working him in more and more because of needs, and he ended up starting two games. Davis estimates he has played safety next to Harrison maybe 200 plays this season.
"It got to the point where safety almost feels natural," Davis said. "The other day we had some injuries at linebacker so I had to play a little linebacker on scout team. It felt odd."
But it didn't look as odd as the look of the Patriots' secondary. The improbable story goes back to the personnel meetings following last year's Super Bowl victory over the Panthers. Belichick decided not to bring back veteran cornerback Terrell Buckley, and the staff felt the team might be short on cornerbacks in case of injury during the regular season.
"After the Super Bowl, our depth at that point wasn't very good," Mangini said. "We thought if we can prepare some people for emergency type roles it would be good. We were looking for somebody in the slot position, which is a tough place to play. In case anything did happen, we would have a player who can move over and have a background in the slot."
Little could be done during the offseason, so Mangini, Belichick and defensive coordinator Romeo Crennel made mental notes of potential candidates. Mangini singled out dependable possession receiver Brown and a few others. In training camp, they gave Brown a try.
"You have to be smart enough to get into both playbooks (offense and defense)," Brown said. "It's not an easy defensive plan. We change the calls from week to week and change our calls during the course of a game. You've got to be able to soak all the stuff up and absorb it all in and transfer it to the field. I had to start taking better care of myself and getting more rest and spending more time at the stadium than I have in the past just to get ready for games."
Mangini had to change Brown's internal thinking. As a receiver, Brown knows where the ball is going and just has to get to the right spot. As a cornerback, Brown has to react to the unknown and do it running backwards instead of forward. In moving Davis to safety, Mangini had to use the raw skills of a 235-pound linebacker who can run.
"It's not like they are going to have me cover Deion Branch or somebody with speed from the slot," Davis said. "They would put me in the box to stop the run or put me back in coverage watching the middle of the field or half the field. I was able to practice and get comfortable with the position."
The next mission was for Crennel and Mangini to prepare young athletes such as Gay and Earthwind Moreland for extended roles in the secondary even though they weren't considered good enough to be drafted. They've had to use other players off the street such as Hank Poteat.
"Randall is very, very smart," Mangini said. "He has the perfect mentality for a cornerback because things don't bother him. He's a steady, hard-working player. For his age, he shows a lot of maturity."
Belichick resisted the temptation to move Wilson from safety to cornerback. Wilson gave the Patriots incredible range in coverage from the safety position. Plus, he developed a nasty streak as a hitter.
"No system can make it work unless you have good players," strong safety Harrison said. "What this system does is put people in the best positions to play. The coaches really teach the guys the scheme and show us different techniques to use."
It helped that Asante Samuel, a second-round pick from a year ago, developed into a budding shutdown cornerback. He limited Marvin Harrison to five catches for 44 yards and Plaxico Burress to three catches for 37 yards during the playoffs. Gay held up surprisingly well for an undrafted rookie starter.
Even more amazing were the stats during the final nine regular-season games after Law and Poole were done. In the Patriots' first seven games, they allowed opposing quarterbacks to complete 56.1 percent of their passes for 232 yards a game. The healthy unit gave up six touchdowns and had seven interceptions in seven games.
The patchwork group allowed 231 yards over the final nine weeks. Opposing quarterbacks completed 60.3 percent of their passes against them and had 12 touchdown passes and had 13 interceptions.
"They play everything out of a two shell," Eagles offensive coordinator Brad Childress said of the Patriots' system. "That's the illusion that it starts with. From there, on the snap of the football, they do a great job of describing what their intentions are. I would just say they just try to keep everybody in front of them. They don't have any problem rushing three and dropping eight on first down, not necessarily just on third and long. They react to what you are giving them and rally to the football."
The system works. It forces quarterbacks to make mistakes without making their own. Sundays become coaching clinics, which is why Davis believes many great coaches will come from this team.
"It's a special season. One you will always remember," Davis said.
John Clayton is a senior writer for ESPN.com.