The Giants needed another kicker with Lawrence Tynes recovering from a bruised quad.
Rhys is one of the NFL's premier kickoff specialists. Over 50 career games, 64 of his 224 kickoffs have been touchbacks.
Rhys first came into the league as a rookie free agent with the Baltimore Ravens in 2005. The Minnesota product has spent most of his NFL career with the Panthers.
To make room on the roster, the Giants waived/injured cornerback Woodny Turenne (calf).