The 5-foot-11, 190-pound Darkwa underwent surgery in May to remove a plate from his left leg, which was broken in 2016.
Darkwa rushed 171 times for 751 yards and five touchdowns for the Giants last season, but it remains unlikely he'll return to the team after the addition of running back Saquon Barkley, the second overall pick in the 2018 NFL Draft, and veteran free agent Jonathan Stewart to its backfield this offseason.
The 26-year-old Darkwa was signed by the Miami Dolphins as a free agent out of Tulane in 2014, but was released after playing only four games that season.
Darkwa signed with the Giants in November 2014 and scored the first touchdown of his NFL career the following month against the then-St. Louis Rams.
In four NFL seasons, he has rushed for 1,038 yards and nine touchdowns.