Gabbert (concussion) fully participated in practice Wednesday, Turron Davenport of ESPN.com reports.
Gabbert technically remains in the NFL's concussion protocol, but his involvement in full practice suggests it likely won't be long before he gains full clearance. He'll presumably take over the backup duties behind Marcus Mariota in Sunday's game against the Bills after Austin Davis served as the Titans' No. 2 quarterback in the Week 4 win over the Eagles.