Josh McCown has significant sprain

TAMPA, Fla. -- Buccaneers quarterback Josh McCown has a significant sprain to his right thumb and likely will miss at least one game, a league source said Saturday.

McCown suffered the injury in Thursday night's 56-14 loss to the Atlanta Falcons and left the game in the second quarter. McCown said he was unable to grip the ball.

The winless Buccaneers (0-3) play at Pittsburgh next Sunday, and second-year pro Mike Glennon is expected to get the start. The Bucs could sign another quarterback or promote Mike Kafka from the practice squad.

McCown, 35, signed a two-year contract with Tampa Bay this past offseason following a productive 2013 season with the Chicago Bears. But the 13-year veteran has struggled in three games with Tampa Bay, passing for just 420 yards, two touchdowns and four interceptions.

The 24-year-old Glennon was a third-round draft pick last year and appeared in 13 games as a rookie, throwing for 2,608 yards and 19 touchdowns with just nine interceptions.