Sinkfield was waived by the Raiders on Tuesday.
In a corresponding move, the Raiders promoted wide receiver Johnny Holton to the active roster. The former CFL star can play both receiver and cornerback but may return to Canada if he cannot find work with another NFL team.
Sinkfield signed with the Vikings on Thursday, Ian Rapoport of NFL Network reports.
Sinkfield spent the 2016 offseason with the Vikings as a wideout, but will join the team as a cornerback this time around. The Northern Iowa product has been impressive in the Canadian Football league over the last three years, recording 102 catches for 1,537 yards and 10 touchdowns over that time frame. Sinkfield may require some time to adjust to playing cornerback, so keep an eye on his progress in order to determine where he will end up on the Vikings' defensive depth chart come roster cuts.