Source: Doug Martin won't play in 2nd preseason game

Tampa Bay Buccaneers running back Doug Martin will sit out Saturday's preseason game against the Jacksonville Jaguars due to bruised ribs, a team source told ESPN.

Martin is sitting out for "precautionary reasons," the source said, and the injury is not expected to affect him beyond this week.

The injury absence was first reported by The Tampa Bay Times and confirmed by ESPN.

Martin was a full participant in joint practices in Jacksonville, including Wednesday's padded practice. It is unclear when he suffered the injury.

As the primary running back in Tampa Bay's run-first offense, Martin totaled 1,402 yards -- second in the NFL -- on 288 carries with 6 touchdowns in 2015. He also had 33 receptions for 271 yards and 1 touchdown.

After Martin, the Bucs have Charles Sims, who missed last week's preseason opener due to an ankle injury but fully practiced this week, and third-stringer Mike James.