Jeremy Kelley is a former CFL and AFL football player that the Colts have signed to a future contract. Mr. Grigson may be displaying his own desire to get a little bigger at the position with this signing. Reguardless of how this project-type receiver pans out, it's comforting to see Grigson continually trying to improve the roster.
I read that Kelley contributed on special teams as well, so Grigson may have signed him more for that role. We shall see