Ben Tate wasn't out of a job for long
The move also came one day after the NFL suspended Vikings running back Adrian Peterson for the remainder of the season.
In Peterson's absense, the Vikings turned to rookie running back Jerick McKinnon and to Matt Asiata on passing downs and goal-line situations.
McKinnon leads the team in rushing this season with 484 yards. Asiata has six rushing touchdowns and one receiving.
Tate was waived by the Browns after getting just two carries for minus-9 yards in a 19-17 loss to the Houston Texans last weekend. Earlier in the week, he complained about lack of carries in Cleveland's three-back system with Terrance West and Isaiah Crowell.
After serving as Arian Foster's backup with the Texans, Tate signed a two-year, $7 million contract with the Browns during the offseason. He leaves Cleveland having played in eight games and rushing for 333 yards and four touchdowns on 106 carries.
Gray played in one game this season for the Vikings and had one catch for 16 yards. He spent the 2013 season with the Browns and had two catches for 8 yards and six rushing attempts for 43 yards in 12 games.