The 26-year-old Colbert was originally a seventh-round pick of the San Francisco 49ers in the 2017 NFL Draft. He spent nearly three seasons in the Bay area before being waived with an injury settlement, but was promptly picked up by the Seattle Seahawks.
Colbert was later signed by the Miami Dolphins, where he played under current Giants defensive coordinator Patrick Graham, off of the Seahawks’ practice squad.
The 6-foot-2, 205-pound safety also spent a few months with the Kansas City Chiefs before being waived on Saturday.
In 27 career games (17 starts), Colbert has recorded 80 tackles, eight passes defensed and two forced fumbles.
Barton, 25, was a seventh-round pick of the Indianapolis Colts in the 2019 NFL Draft. He was waived as a part of final cuts last year before signing with the Chiefs in November.
The 6-foot-7, 302-pound Barton would go on to earn a Super Bowl ring as a member of the championship Chiefs.
Ratley, 25, was a sixth-round pick of the Cleveland Browns in the 2018 NFL Draft and has appeared in 26 career games (six starts), hauling in 25 receptions for 344 yards and one touchdown.
At 6-foot-2 and 200 pounds, Ratley could factor in on the outside.