Story byCharlie BaduiniFri, December 5, 2025 at 8:49 PM UTC·1 min readAaron Glenn provides development update on undrafted rookie quarterback originally appeared on The Sporting News. Add The Sporting News as a Preferred Source by clicking here. New York Jets head coach Aaron Glenn announced today that backup quarterback Justin Fields will be inactive on Sunday due to a knee injury. AdvertisementAdvertisementAdvertisementUndrafted free agent rookie Brady Cook will serve as QB2 when the Jets face the Miami Dolphins in Week 14. It will only be the second time this season that Cook is active on gameday, serving as the emergency third-string quarterback throughout the 2025 season. Aaron Glenn believes Brady Cook will 'be a quarterback in this league'At his press conference, Glenn was asked what he's seen from the former Missouri quarterback in practice."His improvement. He's a very fiery guy.