We saw possible trophies, we saw potential screen shots, now Xbox's official Batman: Arkham City avatar marketplace offerings seem to suggest that Nightwing will at least be a part of -- if not a full-on playable character -- in Rocksteady Studios' upcoming release. While Nightwing doesn't have a full-on costume for sale like Batman, Catwoman, Robin, Joker and Harley Quinn, the avatar store's inclusion of a Nightwing logo tee seems like a pretty strong indication that Dick Grayson will be appearing in the game in some capacity.

Some of the other Arkham City items currently for download at the Xbox 360 avatar marketplace include a Bane mask, Ridler's cane, Two-Face's coin and Catwoman's whip. All this jazz ranges in price from 80-400 Xbox points, which equates to a few bucks after conversion. I'll let your respective Xbox 360 Batcomputers handle the exact calculations.

It should be interesting to see if Nightwing pans out as a playable character, but even if he doesn't, it seems likely at this point that he's going to be a part of Arkham City when it arrives in stores on October 18.