The first time it happened, Cassel went from anonymous backup in New England to starting quarterback in Kansas City with a $60 million contract. This time, it means he is headed to his first Pro Bowl.
"There are so many crazy things, when you look back, about Tom having an injury and me getting my chance," Cassel said Thursday. "It's really weird."
Cassel was picked for the Jan. 30 game in Honolulu because Brady will reportedly have foot surgery to repair a stress fracture. The two are close friends and Brady was one of the first people to call.
"We had a great conversation," said Cassel, who threw a career-high 27 touchdown passes this season and led the Chiefs to their first AFC West title since 2003. "I would have loved to see him go and play because he had an outstanding year. He is a good friend. He's always been super-supportive. He wished me luck. He said go out there and have some fun."
Cassel had not started a regular-season game since high school and might have spent his entire NFL career on the New England bench if Brady hadn't been injured in the 2008 season opener against, of all teams, the Chiefs.
With Brady out for the year, Cassel finally had the chance to prove his mettle and made the most of it, taking the Patriots to 11 wins.
Scott Pioli left the Patriots after that year to become general manager in Kansas City. He was impressed enough to trade for Cassel and hand him the starter's job and a contract with a $36 million guarantee. Cassel's first year, the Chiefs struggled, winning only four games.
But this season went much better and a 10-6 record put the Chiefs in the playoffs. Cassel hit 262 of 450 passes for 3,116 yards, with only seven interceptions to go with those 27 TDs.
He had an emergency appendectomy in December and gained even greater respect among teammates when he missed only one game. He joins three other Chiefs on the AFC squad -- wide receiver Dwayne Bowe, running back Jamaal Charles and guard Brian Waters.
"It's a huge honor," he said. "Being in the league for the last six years, you see the Pro Bowlers going and you go, 'Gosh, hopefully one day I can get there.' I'm really excited."
He can't help but notice how destiny has linked him and Brady and the Patriots and Chiefs.
"There are so many crazy things going when you look back, about Tom having the injury and me getting my chance but that chance was against the Kansas City Chiefs and then myself getting traded to the Kansas City Chiefs," he said. "Now to put me in the Pro Bowl. Again, Tom unfortunately has an injury and he's not able to go. But it also puts me in the Pro Bowl.
"There are so many ironic, crazy things that go on in my career that consist of those [two] little teams or that person."