Hall signed with the Seahawks' practice squad Monday.
The Vikings waived Hall on Thursday, Kevin Seifert of ESPN reports.
Hall completed 17 of 25 passes for 189 yards and two touchdowns in Saturday's 26-3 preseason win over the Eagles. He added 11 rushing yards on two carries.
Coach Kevin O'Connell noted Thursday that Hall will start Saturday's preseason finale against the Eagles.
Hall isn't projected to make the Vikings' 53-man roster, Alec Lewis of The Athletic reports.
Hall (coach's decision) is inactive for Sunday's matchup against the Lions, but he'll serve as the emergency quarterback, Craig Peters of the Vikings' official site reports.
Hall has been demoted to third on the depth chart at quarterback for Sunday's game against the Lions, Jonathan Harrison of SI.com reports.
Hall will cede starting quarterback duties to Nick Mullens for Sunday's regular-season finale versus the Lions, but head coach Kevin O'Connell said Wednesday that he hasn't decided whether Hall or Joshua Dobbs will serve as the team's No. 2 signal-caller in Week 18, Kevin Seifert of ESPN.com reports.
Coach Kevin O'Connell named Hall the Vikings' starting quarterback for Sunday's game versus the Packers.
Hall is expected to be the Vikings' starting quarterback for Sunday's game against the Packers, Ian Rapoport of NFL Network reports.