McCown tore a ligament in his right thumb, and has not practiced since he sustained the injury in Thursday night's 56-14 loss to the Atlanta Falcons.
From the Tampa Bay Times:
"Which quarterback will we start this week?'' Smith said. "There's a good chance it will be Mike Glennon.
"Josh is improving. I like to stay with my standard way of doing things and not talk about starting lineups for the opponent. But Mike took the reps today. How's that?'
Glennon is in his second year in the NFL. Glennon took over for McCown in the second quarter against the Falcons and was 17-of-24 for 121 yards and one touchdown.
The day after the game, Smith said McCown is still the team's starting quarterback.
Tampa Bay is 0-3. The Buccaneers play the Pittsburgh Steelers on Sunday.
- Sarah Barshop