Patrick Mahomes said he had two goals for his new contract when extension talks began with the Kansas City Chiefs earlier this summer: He wanted long-term security and he wanted to leave the Chiefs enough financial flexibility to build a strong team around him.

Mahomes said Tuesday he's confident he attained both by signing a 10-year extension that could pay him up to $503 million and is the richest-valued contract in American professional sports. Combined with the two seasons on his existing deal, Mahomes is bound to the Chiefs through the 2031 season.

"Not only does it give me the security that I've always wanted but also it allows an opportunity for the team to be great around me the entire duration of my career,'' Mahomes said. "I have full trust things will be handled the right way as we go throughout this career and that we will be in a position to win a lot of football games and hopefully win a lot more championships as my career goes on.

"It's an exciting time. I'm just glad that I get to continue to build this legacy in Kansas City.''

Mahomes said he leaned on his father, Pat, and godfather, LaTroy Hawkins, for advice. Both were longtime Major League Baseball pitchers.

"They didn't sign that long-term contract but they saw players who did and ... how they were able to go out there and play free, knowing they had the security that they had always wanted,'' Mahomes said. "The biggest thing they preached to me is kind of the same thing I already thought. It was good to just hear them. You want to have great players around you. You don't want to be a guy that takes up all the money and then all of a sudden you're having to sign different guys that will take cheaper deals. We're going to be able to reward players and keep a lot of these guys around that have built the culture even before I was here.''

To sign for the next 12 seasons required a great deal of trust on the part of Mahomes. It's impossible to know what the Chiefs will have in place around him much beyond the immediate future. Coach Andy Reid, for instance, is 62 years old, although he seems to be enjoying coaching as much now as he ever did. Mahomes said he consulted with Reid before signing such a long extension.

"He said he had no thoughts of being retired any time soon,'' Mahomes said. "Obviously, that's a huge part of it. Having Brett Veach, a young general manager who's done a great job of drafting and putting a lot of great players around me, was definitely another huge boost of confidence to sign this 10-year extension.

"You can't do this with every single organization. When you have an organization with the stability and the culture that we have in the Chiefs' organization, I felt very comfortable. I have a lot of trust that I can do a contract like this knowing that we were going to have that same stability by the time I'm at the end of that contract.''

The Chiefs said they had no problem with giving Mahomes, who is only 24, a long extension. He has yet to disappoint them in his two seasons as their starting quarterback. He was the NFL's MVP in 2018 and last season led the Chiefs to their first Super Bowl championship in 50 years.

"There's still a lot of improvement for Pat in his game,'' Veach said. "He's still growing and learning. He's hungry. He's a special kid. At such a young age he's so mature.''

As the 2018 season started and it quickly became evident what kind of player Mahomes is, Veach met with the Chiefs' salary-cap managers and they started preparing for what he called a "baseball contract'' for Mahomes. Mahomes' deal tops the contract signed last year by Los Angeles Angels star Mike Trout, who signed for 12 years and almost $427 million.

"If there was ever a player that was truly deserving of the largest contract in U.S. sports history, it's definitely Pat Mahomes,'' Veach said.