Hello and welcome to FF Karen! Hard call here; if injuries are serious, the frog might not make it through Winter outside . You could keep at home and care for it all the way through Spring and then release it. From the injury description frog might have been bitten on head; which would explain the sluggishness and listing due to nerve (hopefully) or even cerebral damage (bad). If available; a visit to a Herp veterinary (Arav or Herp Vet Connection) could help determine damage extent, get meds, and receive a professional answer to keep or release question. If a Vet visit is not possible; you can treat open wounds with a plain version (no analgesic) antibiotic like Neosporin or Silver based gel.

In the meantime you can keep it in a large plastic bin container with very damp unprinted paper towels for substrate, a water dish (use dechlorinated tap water for both), and a silk type plant. Change both towels and dish water daily. If clear plastic might need to cover the sides with paper to help frog calm down. Drill some holes in cover for air exchange and you are done.

You can use this care article to provide for the Bullfrog since their requirements are similar: Frog Forum - Leopard Frog Care - Rana pipiens (Schreber, 1782) and R. sphenocephala (1886). Let us know what you decide and we will go from there. Good luck !