John Elway, the team's chief football executive, praised Graham for the character, leadership and play he brought the Broncos for four seasons.
"We're thankful for everything Daniel Graham did for the Broncos and the Denver community. Tough to let him go. We wish him the best," Elway tweeted.
The Denver Post on Wednesday cited Graham's high price tag as the driver behind the Graham's release. He was due to earn a $4.2 million base salary in 2011, along with a $1 million roster bonus.
Graham's play slipped last season, when he had 18 catches for 148 yards but dropped a number of passes.
Three of them missed significant time with injuries last year.
Harris suffered a high ankle sprain in the preseason finale and missed much of the first half of the season before starting the final eight games. The Broncos improved 1.8 yards per carry after he was reinserted into the lineup in Week 10, the highest such leap over that stretch.
He also protected southpaw Tim Tebow's blindside when the rookie quarterback started the final three games of the season.
Prater made 16 of 18 field goals and scored 76 points before missing the final month with a groin injury, and Woodyard dealt with leg injuries much of last season.
Thomas had 36 tackles last year and joined Rubin Carter (1975-77) as the only interior linemen in Broncos history to start every game during his first three seasons. Vickerson joined the team as a free agent after his release by Seattle and started 12 games, collecting 52 tackles and two sacks.
The Associated Press contributed to this report.