Baltimore placed Fuller (ACL) on its injured reserve list Tuesday, Aaron Wilson of ProFootballNetwork.com reports.
Fuller tore his ACL during Baltimore's 24-9 victory at the Jets Sunday, Jonas Shaffer of The Baltimore Sun reports.
Fuller signed with the Ravens on Tuesday, Jeff Zrebiec of The Athletic reports.
Fuller recorded nine total tackles (eight solo) in the 28-13 divisional win against Los Angeles on Sunday.
The Broncos announced Monday that Fuller will serve as the primary slot cornerback going forward, Mike Clay of ESPN.com reports.
Fuller was active but didn't play in Thursday's 17-14 loss to the Browns.
Fuller recorded six tackles and allowed five receptions on eight targets in Sunday's 27-13 win over the Giants.
Coach Vic Fangio said of Fuller, "We're going to do everything we can to get (him) back to that 2018 form," Aric DiLalla of the Broncos' official site reports.