OKLAHOMA CITY -- Now that they're no longer teammates with the New England Patriots, wide receiver Wes Welker admits his friendship with quarterback Matt Cassel has changed.

After spending years as a backup in college and the NFL, Cassel finally got his moment in the sun last season after Patriots starter Tom Brady was injured in the opening game. The Patriots put the franchise tag on Cassel after the season, then traded him to Kansas City, where he'll make almost $15 million this season as the front-runner to be the Chiefs' starting quarterback.

"I'm very happy for him because now he can pick up all the restaurant bills and things like that," Welker said Saturday at the charity football camp he holds each year at his former high school. "If I ever need a loan, I can always come to him."

But Cassel, who came along to serve as one of the celebrity coaches, merely mused at "how jokes change from one year to the next."

"He's still picking up everything," Cassel said.

For one day, that includes the tab for the camp, through Welker's 83 Foundation, that was entirely free for the 360 at-risk children ages 5 to 12. The turnout was the most in the camp's four-year history, and three times as big as it was on a rainy day last summer. The kids faced temperatures around 100 degrees on the fields at Heritage Hall High School.

"Looking at it from when I was younger, this is like a once-in-a-lifetime type of opportunity that a lot of kids wouldn't have that opportunity," Welker said. "So, getting to have this camp for them, it's fun for me. A lot of times when you do paid camps, the kids don't appreciate it as much as these kids. They really appreciate it, and they really kind of grasp onto you and they're very grateful for what you're doing."

When the camp got started, the players headed out to show off their strengths. Welker, who tied the Super Bowl record for receptions with 11 in a loss to the New York Giants two seasons ago, showed kids the right way to catch a ball while Cassel taught others the basics of the three-step drop a field away.

New York Jets linebacker Larry Izzo, another former Patriots teammate of Welker's, also returned to the camp and pledged to keep coming back.

"It's kind of the turnover of the NFL," Welker said. "You have the guy here, and then you don't. You develop good friends, and then they leave.

"Larry and Matt are great guys, and they were more than willing to come out here. We're all good friends. We talk all the time. Being able to have them here, even though they're with different teams, goes to show you that they're actually good friends."

Cassel said he and Welker clicked right away -- both on and off the field -- when they became teammates.

"He's a good friend of mine, and any time you can help -- and especially when it comes to kids -- I always love to pitch in a helping hand," Cassel said.

The two will part ways again as the season approaches, with Cassel likely having his first chance to be a full-time starter after serving as a backup to Carson Palmer and Matt Leinart at USC and then to Brady in New England. Cassel threw for 3,693 yards and 21 touchdowns last season while filling in for Brady.

"It's just been a whirlwind of change this last year and a lot of opportunity," Cassel said. "I was fortunate enough to get an opportunity last year to step in and play, and now we've got a new season ahead of us with a new team, a lot of new faces, and I'm excited about the challenge of it."

Welker, who tied for the NFL lead in receptions two seasons ago during the Patriots' perfect regular season, will readjust to having a rehabilitated Brady throwing him passes again.

"It's been good, as far as I can see," Welker said. "This spring, he was out there. He's probably a little rusty, but at the same time, he was Tom Brady. He's making all the right reads, all the right throws. He's excited and he's ready to be back, and he's hungry."

For one weekend, that's all on hold for a greater cause. In addition to the camp, Welker's foundation is working to build a fitness center with weights and exercise machines for children at a new Boys & Girls Club facility in Oklahoma City.

"We're just trying to inspire these kids through athletics and positive role models," Welker said. "And that's what we're trying to be today: just a positive role model to all these kids and let them know that somebody's here for them."