Michael was sent to the Cowboys on Sunday for a conditional 2016 draft pick.
Defensive end Lavar Edwards was waived by Dallas to make room on the 53-man roster.
Michael was a second-round pick out of Texas A&M in the 2013 draft. He ran for 254 yards over 14 games the past two seasons with the Seahawks after running for 2,791 yards and 34 touchdowns in four seasons for the Aggies.
After losing NFL rushing leader DeMarco Murray in free agency during the offseason, the Cowboys have multiple options at running back this season. Michael joins Joseph Randle, Darren McFadden and Lance Dunbar in Dallas.
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