Williamson (hamstring) reported to Triple-A Durham on Tuesday to begin a rehab assignment, Marc Topkin of the Tampa Bay Times reports.
The 25-year-old landed on the shelf in early August due to a strained hamstring, but he's been cleared for game action after recently resuming baseball activities. Williamson has a .247/.309/.332 slash line with three homers and eight steals in 84 games this season, and he may only need a few games in the minors before rejoining the Rays.