Thompson signed with the 49ers' practice squad Wednesday, Matt Maiocco of NBC Sports Bay Area reports.
At his best, Thompson was one of the better passing-down backs in the league, but he's now 30 years old and hasn't played more than 11 games in a season since 2016. He has a history with 49ers head coach Kyle Shanahan, who was Washington's offensive coordinator in 2013 when Thompson played all of zero offensive snaps in four games as a rookie fifth-round pick. He'll now have a chance to work his way up the depth chart for an injury-riddled 49ers team that just lost JaMycal Hasty to a knee injury. Raheem Mostert (knee) is already out for the year, Jeff Wilson (knee) is on the PUP list, and even Elijah Mitchell (shoulder) and Trey Sermon (concussion) are uncertain to play Sunday against the Packers while they manage injuries.