Garrett (ankle) will begin a rehab assignment at Double-A Harrisburg on Saturday, Mark Zuckerman of MASNSports.com reports.
Garrett has been on the injured list all season after undergoing left ankle reconstruction surgery in August, and it appears he's now ready to test his ankle in a competitive setting. It's unclear how long he will remain in the minors, but the 28-year-old outfielder figures to operate on the short side of a platoon once he returns to the Nationals.