The Redskins also waived Martez Carter with an injury designation on Saturday.
Darkwa has visited or worked out for the Colts and Jets in recent weeks and previously met with the Bills and Patriots.
Darkwa, 26, originally signed on with the Dolphins as an undrafted free agent out of Tulane back in 2014. He spent just a few months in Miami before he was signed off of their practice squad by the Giants.
New York brought Darkwa back on an exclusive rights contract in 2016 and re-signed him to a one-year contract last year.
In 2017, Darkwa appeared in 15 games for the Giants and rushed for 751 yards on 171 carries (4.4 YPC to go along with 19 receptions for 116 yards receiving and five total touchdowns.
We have him featured in our Top 50 Available 2018 NFL Free A