It could be part of his general weight gain.
That picture's over a year old, maybe closer to two. RDA underwent a series of surgeries on his shoulder, knee, and foot. The foot surgery didn't heal quickly and he spent three months in bed and gained 35 pounds. This is an active guy who was still playing ice hockey in his 50s. But with that much pain, Cortisone is a possibility. Did the SGU episode show his full body or was it just head and shoulders?