Mitchell will begin practice on Sunday
Mitchell was at Chiefs mini-camp in street clothes but will begin practicing Sunday, coach Dick Vermeil said.
"We're very happy to have him here and I think he's happy to be here," Vermeil said. "He's in a good frame of mind and his attitude is very good."
Mitchell, who played in 63 games in four seasons at Philadelphia, fell into disfavor with Eagles coaches and teammates after making a series of controversial and inflammatory statements.
He insulted the Patriots secondary before the Super Bowl, and also called out New England coach Bill Belichick. He also criticized his teammates for not backing him and blasted quarterback Donovan McNabb for not throwing to him more.
"The plays are going to be there for me to make," Mitchell said after the Chiefs went through a two-hour workout in front of about 15,000 fans. "I just want to help the team win and hopefully be utilized catching the ball. So it's going to be good. I'm happy to be here."
Mitchell's one-year contract includes a base salary of $540,000, the NFL minimum for a four-year veteran. Because he failed to reach any of the performance or playing time incentives in his initial contract with Philadelphia, which would have triggered "escalators" that raised the base salaries in later years, Mitchell was slated to earn the minimum with the Eagles as well. So, from a financial standpoint, changing teams did not cost him anything.
Mitchell, picked in the first round out of UCLA in 2001, also labeled himself with a seemingly endless list of self-promoting nicknames like "The People's Champ," "FredEx," and "First-Down Freddie." But he hardly produced, catching 90 passes for 1,263 yards and five touchdowns in his career.
The move comes a day after free-agent receiver Az-Zahir Hakim changed his mind and decided against signing with the Chiefs.
Information from The Associated Press was used in this report.