I think you should contact your local SPCA to come pick him up. If he's hurt then hoping his owners find him really isn't a good solution. For the best interests of the cat he needs medical attention, which the SPCA can provide.
Chase (Friendly Resident Wigglebum) - Border Collie/Lab/Shepherd X
Kailey (Misunderstood Gentle Beauty) - GSD & foster failure #1
Rupert (Gold-Medal Winner of the 3 a.m. Kitty Destruction Olympics
Heidi - RIP my sweet baby girl