In addition to Welker, Denver also came to terms on a two-year deal with with former Jacksonville defensive tackle Terrance Knighton, and a one-year contract with linebacker Stewart Bradley, who played with the Arizona Cardinals the past two seasons.
After playing his first three seasons with the Cardinals, Rodgers-Cromartie spent the past two seasons with the Philadelphia Eagles.
Rodgers-Cromartie, expected to become a starter at right cornerback with the Broncos, struggled with the Eagles. A Pro Bowler in 2009, Rodgers-Cromartie has 16 interceptions in 77 career games.
In Denver, Rodgers-Cromartie will join one of the AFC's best teams and will play alongside 12-time Pro Bowler Champ Bailey.
Although the deal with Welker received a bulk of the attention, the Bradley and Knighton deals also could influence Denver's starting lineups.
Bradley played last season for Arizona, where he didn't fit in with the team's 3-4 scheme. His best season came in Philadelphia in 2008, when he had 108 tackles. He will compete with Nate Irving and Steven Johnson for Denver's starting middle linebacker spot.
"Obviously, the standards on both sides of the ball are high here," said Bradley, who found out he was cut from the Cardinals while on his way home from his honeymoon. "I think it's a great combination when you can have a stout, strong defense on a team with a prolific offense."