Special teams, and specifically kick returns, have been a solid area of the team so far in 2012 and we need that to continue vs NE. However, at this point, given our injuries, Cro and Kerley are too valuable to put back there on kick returns.
Grimes was a returner in college, but that was more due to the lack of competition in my opinion as he runs 4.5ish 40.
Gates (if healthy) has a lot of speed and could take one of the 2 open spots (mcknight and powell) on the gameday roster.
Jason Hill also could be intersting as he is a fast/quick player, although Im not sure if he has any experience returning.
Kyle Wilson was a Punt returner in college and has occaisonally worked there in the pros, but also falls under the "defensively valuable" category with Revis already out.