Darby was elevated from the practice squad to the active roster by the Falcons on Saturday, Scott Bair of the team's official site reports.
The depth wide receiver seems to be replacing Mack Hollins, who is out for Sunday's game against the Cardinals with an ankle injury, per Bair. Darby, a 2021 sixth-round pick, has yet to appear in a game this season. Darby recorded two catches for 29 yards and no touchdowns over his first two NFL seasons.