The Vikings are turning back to quarterback Nick Mullens for Sunday's regular-season finale against the Lions, coach Kevin O'Connell announced Wednesday.

Mullens will make his third start for the Vikings — his second against the Lions after throwing for 411 yards, two touchdowns and four interceptions in a 30-24 Dec. 24 loss. Those interceptions weighed heavily in the Vikings' one-score loss and led to switch from Mullens to rookie quarterback Jaren Hall as the starter for Sunday's 33-10 loss to the Packers. Mullens replaced Hall after halftime.

"Nick has been very effective moving the team," O'Connell said Wednesday. "We've been very explosive as an offense when he's been in there. Nick knows the one area that we must focus on is possession of the football and not giving the football away."

In Mullens' two starts against the Bengals and Lions, the Vikings offense has averaged 407 yards and 24 points but also three turnovers in each loss.

O'Connell noted Mullens' experience in the playbook. He has been on the team for 16 months compared to Joshua Dobbs' two months in Minnesota.

The coach declined to reveal which quarterback will be the No. 2 in Detroit, saying the team is "working through that."

"[Mullens] has got a lot of reps logged as our backup over the last two years," O'Connell said. "Really every game he's started, we're very competitive all the way down to the end. You look back on those two, three, four plays here and there that if we can just maintain possession of the football, what would that mean?"

This will be the Vikings' fifth change at starting quarterback entering the ninth game since Kirk Cousins suffered a torn Achilles tendon on Oct. 29 in Green Bay.

Mullens replaced Dobbs in the fourth quarter of the Dec. 3 victory at Las Vegas. He started the next week in a loss at Cincinnati, where he threw for 303 yards and two scores but also two interceptions.

Receiver Justin Jefferson said the season has been a roller coaster because of all the injuries, turnovers and quarterback changes.

"Yeah, it's difficult," Jefferson said. "Talking for myself, I feel it doesn't matter who's throwing me the football. I feel if it's in my area to catch, I'm going to catch the ball."

He also said the playbook is challenging for all players, especially quarterbacks.

"It's not an easy role," he added. "We have one of the most difficult offenses in the league, and especially when we have had our starting quarterback that hasn't been hurt since I've been here."

Offensive coordinator Wes Phillips was asked if the struggles from backup quarterbacks indicates the offense is difficult on them.

At times, the Vikings have asked Mullens, Dobbs and Hall to sort through multiple play calls at the line of scrimmage with the play clock ticking — just as Cousins did with mastery in his second season running the system.

"I think if you're too basic you will get exposed by defenses," Phillips said. "I do think there should be some balance there, and some plays are certainly easier than others that we call."

"With that comes a lot of learning on the front end," he added. "Sometimes calling multiple plays in the huddle, understanding what the criteria is to either stay with the play or get to the next play. All those things can be challenging. … There are offenses that are simpler."

Coaches have also asked backup quarterbacks to throw a lot.

Cousins' weekly averages over eight starts of 27 completions on 39 attempts for 291.4 yards all lead the league. Dobbs averaged 30 throws over his five appearances. Mullens attempted 69 passes in his two starts. Hall dropped back on 14 of 23 plays in the first half against the Packers before he was pulled.

O'Connell was asked to look back and reflect on what happened with Dobbs, who made a fabulous debut with a thrilling Nov. 5 victory at Atlanta only days after arriving in Minnesota via trade from Arizona. But Dobbs' run lasted only four starts.

O'Connell reiterated that defenses adjusted to Dobbs' mobility. He was unable to consistently throw for yardage in this offense, completing 10 of 23 throws for 63 yards before he was pulled for the last time in Las Vegas.

"You put that on tape enough and people start trying to defend you certain ways," O'Connell said. "I still have a lot of confidence in Josh, I do. I think it is remarkable what he was able to come in here and do, and if called upon this weekend, I have confidence that Josh will go in there and be prepared."