Defensive end Vonnie Holliday, who joined the Denver Broncos on Sunday for his first workout with his new team, says an injured knee is what prevented him from signing a contract this spring.

Holliday, who signed with the Broncos on Saturday after Le Kevin Smith missed Denver's final two preseason games with a knee injury, told The Associated Press after practice that he had his right knee surgically repaired by noted sports surgeon Dr. James Andrews in late January.

"A lot of people don't know this, but I had my knee cleaned up and then I got released by Miami and I found myself in free agency: a 12th-year pro, 33 years old and coming off knee surgery," Holliday said. "So, when I met with the Broncos I had a puffy knee."

Still, the Broncos stayed in touch and came calling Saturday.

"I really didn't want to miss training camp," said Holliday, who stayed in shape by working with a trainer and a nutritionist in his hometown of Atlanta. "When you're going through it, you hate it and you dread it. But I missed it because I was used to being in training camp.

"And retirement was never an option, not from where I'm at right now. I still have a few years left."

Holliday, who started 15 games for the Dolphins last season and led the team's defensive linemen with 46 tackles while compiling 3 1/2 sacks, signed a one-year deal with the Broncos.

He said he had a good workout Sunday _ the media weren't allowed to watch any portion of practice nor were reporters allowed access to players or coaches afterward.

"It was nice to get back out there on the football field," Holliday said.

The Broncos also welcomed back receiver Brandon Marshall, whose suspension for insubordination ended Sunday. However, the team didn't announce his reinstatement or a corresponding roster move.

Holliday began his career in Green Bay, where he was a first-round pick out of North Carolina in 1998. He also played for Kansas City before joining the Dolphins in 2005. Miami released him in March rather than pay him a $1.5 million roster bonus.

Holliday spent most of his career playing in the 4-3 scheme but has the ideal body size, strength and long arms to play in the 3-4. He started at end in the Dolphins' 3-4 scheme last year and said part of what he'll bring to Denver is the knowledge of that system that he can impart to his new, young teammates.

Holliday is the third Dolphins starter from last year to sign with the Broncos as an unrestricted free agent, joining free safety Renaldo Hill and cornerback Andre' Goodman.

NOTES: The Broncos' eight-man practice squad includes TB Darius Walker, their leading rusher in the preseason. The others: TE Marquez Branson, CBs Tony Carter and D.J. Johnson, G Mitch Erickson, LB Braxton Kelley, DL Everette Pedescleaux and WR Matthew Willis.