The Ravens exchanged Gradkowski and a 2016 fifth-round NFL draft pick to the Broncos in exchange for the Broncos' 2016 fourth-round draft pick, according to a league source.
Gradkowski was slated to be a backup for the Ravens, but could wind up starting for the Broncos.
The trade becoming official is contingent on Gradkowski, who has had knee issues, passing the Broncos' physical.
Trading Gradkowski saves the Ravens roughly $1 million against the salary cap.
Gradkowski hit an escalator clause heading into the final year of his rookie contract. He is now due a $1.542 million salary, up from $660,000, and is expensive for a backup. His salary cap figure was $1.663 million.
Because of his high cap figure and being a reserve, Gradkowski was likely in a vulnerable roster situation if he hadn't been traded.
The trade reunites Gradkowski with former Ravens offensive coordinator Gary Kubiak and quarterbacks coach Rick Dennison, the Broncos' new head coach and offensive coordinator, respectively.
A 2012 fourth-round draft pick from Delaware, Gradkowski played sparingly behind starter Jeremy Zuttah after starting every game during the 2013 season. Gradkowski was previously the backup to six-time Pro Bowl center Matt Birk during his rookie season.