Ayers (ankle) practiced in a limited capacity on Wednesday, Greg Auman of the Tampa Bay Times reports.
Ayers participated for the first time since suffering the ankle injury Week 2, albeit in shorts as the Buccaneers limited his activity. If he's unable to return to game action Sunday against the Raiders, Noah Spence figures to once again get the start at defensive end.
Martin (hamstring) didn't practice Wednesday, Greg Auman of the Tampa Bay Times reports.
Already beset by one setback, Martin will be treated with kid gloves by the Buccaneers as he rehabilitates the balky hamstring that has sidelined him since Week 2, per Auman. As a result, the training room will be Martin's domain until he's cleared to return to the practice field. In the interim, the Bucs will entrust Jacquizz Rodgers with a particularly hefty workload, which has equated to 56 carries for 255 yards and six catches for 37 yards over the last two contests.
McDonald (hamstring) will not play against the 49ers on Sunday.
McDonald was able to return to practice after sitting out on Wednesday, but will be held out due to the lingering nature of hamstring injuries. However, he appears to have an optimistic chance of returning next week. Akeem Spence will get the start on Sunday as his replacement.
Bell (concussion) reached an injury settlement with the Buccaneers on Thursday, Aaron Wilson of the Houston Chronicle reports.
Bell suffered a concussion in Week 4's preseason finale against the Redskins, leaving him on the sidelines for an extended amount of time. The team decided to part ways with wideout instead of holding him on IR for the year.