The Raiders signed Gentry off Cincinnati's practice squad Wednesday, Tom Pelissero of NFL Network reports.
Gentry will join Las Vegas' active roster and will provide depth in a tight-end room that's dealing with injuries to Michael Mayer (toe) and Jesper Horsted (hamstring). Both Mayer and Horsted missed Monday's 20-14 win over the Chiefs, and if they remain out Sunday against the Colts, only Austin Hooper would slot in ahead of Gentry on the depth chart.