They'll open again on Friday at 6AM and stay open until 10PM. Note that store hours can vary by location, so it's a good idea to find your closest Sports Authority and double-check with them for their specific Black Friday hours.
There are 20 pages of Sports Authority Black Friday deals-432 to be exact-in their Black Friday ad this year. Start your shopping at 6pm-Midnight Thanksgiving night, and Friday from 6am-10pm. (store hours may vary).