The Red Sox designated Kelly (elbow) for assignment on Monday, Chris Cotillo of MassLive.com reports.
Kelly spent most of the second half of the regular season on the 60-day injured list for the Red Sox. He appeared in 17 games out of Boston's bullpen prior to the injury, recording a 3.31 ERA, 1.29 WHIP and 14:7 K:BB across 16.1 innings.