Bortles' status was in doubt after he sustained a mid-foot sprain in his right foot in Jacksonville's 20-12 loss to the Ravens in Baltimore last Sunday. He did not practice on Monday and was limited in practice on Tuesday and Wednesday.
According to Hays Carlyon at Jacksonville.com, Bortles took the practice field for 30 minutes on Thursday, huddling up with coach Gus Bradley, quarterbacks coach Frank Scelfo and others after his workout.
Bortles, 22, has appeared in 12 games this season, starting 11. He has completed 61 percent of his passes, throwing for 2,676 yards, 10 touchdowns and 17 interceptions.
The rookie out of Central Florida was selected third overall by Jacksonville in this year's draft. His start against the Titans will be his first in NFL primetime.
The Jaguars are 2-12 and fourth in the AFC South. The Titans, also 2-12 and third in the AFC South, defeated Jacksonville 16-14 in their Oct. 12 matchup in Tennessee.