The Dolphins got a one-week roster exemption for Gado, which means he won't play against the Giants on Sunday but the Dolphins won't have to clear a roster spot for him until next week.
Gado appeared in three games with Houston this season, rushing for 46 yards on 18 carries with one touchdown.
His best season came as a rookie in 2005 when he rushed for 582 yards and six touchdowns for the Packers after stepping in for an injured Ahman Green.
Gado is a 24-year-old native of Kufai, Nigeria, who played his collegiate ball at Liberty University.
His addition might mean that Lorenzo Booker's days on the inactive list could continue.
The third-round pick was Florida State hasn't been in uniform on game day yet, but it was assumed he would become the third running back after Ronnie Brown was placed on injured reserve.