Gray was a quarterback and wide receiver in college for Minnesota and after a position switch spent last season with Cleveland. Harris played the past two years for San Diego.
The Vikings also signed nine players to their practice squad, leaving one spot open: running back Joe Banyard, wide receiver Kain Colter, defensive tackle Isame Faciane, tight end Chase Ford, wide receiver Donte Foster, cornerback Kendall James, center Zac Kerin, offensive tackle Mike Remmers and defensive end Justin Trattou. All nine were cut by the Vikings on Saturday in the reduction to 53 players for the regular season.
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