ATLANTA — The Vikings traded for Joshua Dobbs on Tuesday, and prepared to make him their backup quarterback on Sunday against the Falcons.

By the end of the first quarter, he was their only QB.

After Jaren Hall led the Vikings on a 74-yard drive highlighted by a 47-yard completion to Alexander Mattison, the rookie QB sustained a concussion while trying to run for the end zone on a third down and absorbing a hard hit from Falcons cornerback Jeff Okudah before linebacker Nate Landman landed on him. Right tackle Brian O'Neill immediately waved for the Vikings' medical staff when Hall went down, and the Vikings quickly ruled Hall out after a brief examination.

Hall finished 5-for-6 for 78 yards, while running twice for 11 yards. Dobbs threw for 1,569 yards, eight touchdowns and five interceptions in eight starts with the Cardinals before the trade to Minnesota.

In his first drive for the Vikings, Dobbs was sacked in the end zone on third down for a safety. On his second, he was sacked and fumbled at the Minnesota 26. The Falcons recovered and eventually kicked a field goal to take a 11-3 lead.

But once he got settled in the Vikings offense, he led three touchdown drives, made key plays on scrambles and delivered a 31-28 win on a 6-yard TD pass to Brandon Powell with 22 seconds left.

He completed 20 of 30 passes for 158 yards and two touchdowns and rushed for 66 yards and another score.

Hall's concussion was not the only injury suffered by the Vikings offense, which began the game without quarterback Kirk Cousins, receiver Justin Jefferson and left tackle Christian Darrisaw, who was ruled inactive with a groin injury Sunday morning.

Late in the second quarter, receiver K.J. Osborn also left the game with a concussion after taking a hard hit to the head that was penalized. He was alert when he was carted off the field.

In the second half, Vikings running back Cam Akers left with an ankle injury that coach Kevin O'Connell said is feared to be an Achilles tear.

Cousins is out for the season after tearing his right Achilles tendon last week in Green Bay.