SAN DIEGO -- Drew Brees and LaDainian Tomlinson had a secret pact. After entering the league in the same draft class (2001) with picks the Chargers got from the Falcons in the Michael Vick trade, Brees and Tomlinson vowed to stay together until they won a Super Bowl.
"I was kinda in denial at first," Tomlinson said of the beginnings of the transition. "People would say Drew won't be here. I'd say, 'No, he'll be here, he'll be here.' It was like, 'Wow.'"
An outsider would have had a hard time taking over this team. Brees meant that much to the Chargers. He was everyone's friend. His mental toughness and tenacity captured the heart and soul of this team. But because Rivers invested two years in the same locker room soaking up everything from Brees, he was able to step right in. The transition was natural. The Chargers believe Rivers can get the job done.
While all the Chargers can do is wait until the regular season to find out whether what they're seeing on the practice field translates into wins, they look every bit like a playoff contender with Rivers behind center.
Face it: The transition was inevitable. Brees was making $10 million. Rivers completed the second year of a six-year, $40 million deal having barely played. In the salary cap era, two high-priced quarterbacks can't stay together for very long. The separation of the two, though, was emotionally wrenching. Most thought Rivers should have played the meaningless season finale against the Broncos. The Chargers were out of the playoffs. Coach Marty Schottenheimer felt it was important to get that 10th win, so Brees started. Rivers rushed in to replace Brees and struggled without the benefit of the week to prepare.
"The whole way it played out was tough, it really was," Rivers said. "Drew being injured, which nobody wanted to see happen, made it tough. I hadn't played in 15½ games. It was raining. It was a tough half. But I think that half helped me more than I know. I saw those bullets flying at me from a really good defense, and it left that taste in my mouth. I just think that I really believe I gained more than a half of experience in that game."
With Brees, the Chargers tasted the playoffs. Rivers' challenge is to bring them back to that pedestal. In some ways, Rivers is in a better position than Brees was when he took over in San Diego in 2002. Brees was the starter on a Chargers team that was in the beginning of a rebuilding process. The receivers weren't very good and tight end Antonio Gates had yet to become one of the game's most dangerous weapons. It was Tomlinson and Brees basically doing it all on offense.
"It's a pretty natural transition," Tomlinson said. "He's going into his third season. He doesn't have the experience, but the intangibles he has are all there. He's tall. He has a good arm. He can see the field. I really think he's a smart quarterback who is ready to play. Drew had game experience. He could feel what's going on and go to the line of scrimmage, and he could adjust. Early on, the coaches may not let [Rivers] do that."
In some ways, Brees isn't completely gone. Knowing the Chargers were Brees' team for two years, Rivers, who's considered one of the brightest quarterbacks to come along in years, studied what made Brees successful. He copied Brees' game preparation rituals. He watched how Brees evolved into one of the NFL's best game managers.
But it also would be foolish to think Rivers will step to the line of scrimmage on Sept. 11, when the Chargers open in Oakland, with the extensive game plan that was available to Brees, who had four full seasons as a starter. Offensive coordinator Cam Cameron will protect Rivers early with simpler game plans.
"I believe he has the right stuff," Schottenheimer said. "The only thing none of us can project is the time frame. There is a period of adaptation from the time you are sitting on the pine to when you go out there. What we don't want to do is overload a young player because all of a sudden there is so much information that he can't process it and have it become second nature. He's going to be a good player."
"Philip has the whole package. People talk about his arm strength not being strong enough because he has a weird delivery. I don't buy that. I think he's going to be a fantastic quarterback. He has the intangibles to be successful. I think on talent he can be better than Drew, but I don't know how the package is going to develop."
A.J. Smith, Chargers general manager, on Philip Rivers
Smith doesn't doubt that. He traded away Eli Manning, who didn't want to be a Charger, for the chance to get Rivers in the 2004 draft. It was one of the biggest personnel gambles in years. Manning took the Giants to the playoffs last season in his first full year as the starter. The book on Rivers hasn't been written yet.
"Philip has the whole package," Smith said. "People talk about his arm strength not being strong enough because he has a weird delivery. I don't buy that. I think he's going to be a fantastic quarterback. He has the intangibles to be successful. I think on talent he can be better than Drew, but I don't know how the package is going to develop."
At 6-foot-5, Rivers is much taller than Brees. Smith and Schottenheimer love his quick release. On the field, he's a more vocal leader than Brees, who was more of a quiet presence in the huddle.
"I think you've got to be able to lead," Rivers said. "The one thing I focused on the last two years is establishing some of that leadership. I took the backseat because I should have. I had put in a little foundation of leadership in case this opportunity came. At the same time, I went back to the fundamentals and worked on my drops, my footwork and the way I carry the ball. I tried to fine tune it as much as I could."
Unlike Brees, Rivers doesn't have to take this team from scratch and build it into a winner. Brees inherited a five-win team in his first year as a starter. The Chargers have won 21 regular-season games over the past two years. The defense is young, powerful and emerging as potentially dominant.
Rivers can rely on Tomlinson, Gates and Keenan McCardell, a deep backfield and emerging young receivers.
"I think we've arrived as a good football team that should be postseason bound," Smith said. "When you go to the postseason, things take care of themselves. Postseason means you're a good football team. And in one of those special years, you can put everything together and it can happen. But you need to grow, feel the pain of losses. I think we're a good football team."
The Chargers offered Brees a $10 million-a-year contract to stay, but only $2 million of it was guaranteed. The Saints topped that. Now, the Chargers move on to Rivers. It's his time. So far, it appears to be a natural fit.
John Clayton is a senior writer for ESPN.com.