Two days after a pair of joint practices got them more than 80 snaps against the 49ers' first team, nearly all of the Vikings' starters emerged from the U.S. Bank Stadium in baseball caps on Saturday evening, set to watch the team's reserves play the San Francisco 49ers' backups in a half-empty stadium.

Quarterback Kirk Cousins was one of those 27 players the Vikings didn't put on the field. It's entirely possible a quarterback who'll back up Cousins this season wasn't on the field, either.

The Vikings' 17-7 loss to the 49ers on Saturday night did little to assuage concerns about the team's backup quarterback situation, certainly not after Minnesota gained just 53 yards in the second half and especially not after Kellen Mond followed up two second-half touchdown throws in Las Vegas on Sunday with two interceptions at home.

Minnesota gained just 53 yards in the second half and turned the ball over three times (two on Mond interceptions, one on a fumbled Ihmir Smith-Marsette punt return). The Vikings went just 2-for-11 on third down, running only 50 plays and holding the ball for just 22:15.

In a normal game situation, coach Kevin O'Connell said, he might have called a few more run plays to get the offense into a rhythm. Saturday night, the Vikings' quarterbacks dropped back 36 times, in a game the coach hoped could be a showcase for Mond and Sean Mannion.

It ended with the backup QB question still lingering over the Vikings' roster.

"Ultimately, you would love to have come out of tonight feeling like, 'Shoot, they both moved the team and scored a lot of points, and we've got a heck of a hard discussion and conversation ahead,'" O'Connell said. "Because as we've talked about, in my mind, the clock is going. Although I feel like our starters are in a good spot for Sept. 11, and that's where our emphasis is really on, there's a lot of jobs we've got to still allow to play themselves out."

The Vikings' final preseason game, on Saturday night in Denver, could again be about Mannion or Mond trying to claim the No. 2 job (especially if the starters rest again). Both of them might need the opportunity to make a strong case.

Mond drew praise from O'Connell on Sunday after throwing two second-half touchdown passess against the Raiders in Las Vegas, and the Vikings entered Saturday night hoping to see more development from their second-year quarterback. But after hitting throws of 11 and 16 yards — stepping up and escaping the pocket before finding Bisi Johnson on the latter play — Mond missed two throws, including one that led to the Vikings' first turnover of the preseason.

He overthrew Johnson downfield, and two plays later, Mond stayed in the pocket and threw with pressure in his face that caused him to shorten his delivery. His pass floated short of Johnson on another out route, and the 49ers' George Odum intercepted the pass.

"I felt like I was efficient in some really big ways, but some other ways missing some throws and some reads," Mond said. "Just got to go back, watch the film tomorrow, make corrections and get better."

Mond finished 10 of 20 for 82 yards and the two interceptions. Mannion went 10-for-15 for 65 yards, leading the Vikings on their only touchdown drive near the end of the first half with connections to Trishton Jackson and Smith-Marsette, who gained 8 yards on an underneath route to pick up a first down at the 49ers' 3. Ty Chandler punched the ball into the end zone on the next play, behind blocks from Ingram and Austin Schlottmann, to put the Vikings up 7-3 with 1:39 left in the first half.

"With Sean, when you call something, you feel strongly about the execution level being high, because you know he's gonna communicate, articulate that play, and then he's gonna go out and do his job," O'Connell said. "I think Sean's at his best when he doesn't try to do too much, and he throws completions, puts the ball in play to the guys around him, helps lead the charge from the communication standpoint. He's a very smart player, and you feel that veteran presence when he's in there with those guys. But ultimately would have loved to see a couple more drives like that for both him and Kellen."

Robbie Gould's field goal made it 7-6 Vikings after two quarters. The Vikings would not get a first down after halftime until Mond hit Jake Bargas for 14 yards with less than four minutes to play.

The 49ers outgained the Vikings 138-5 in the third quarter, and put the game away with a Gould field goal at the 4:09 mark in the fourth quarter. Mond's final throw of the night was also intercepted; he floated a deep ball for Jalen Nailor near the Vikings' end zone, and San Francisco safety Tayler Hawkins undercut the throw.

Nailor was supposed to run a fade route on the play, but kept his route on the numbers rather than driving it away from Hawkins to the corner of the end zone. Still, Mond said, "I gave the safety an easy pick. That was a really bad mistake on my part."

The Vikings' cautious approach with their starters didn't leave them without a concerning medical moment; cornerback Andrew Booth limped off the field in the second quarter, and was ruled out after the Vikings' medical staff found he'd aggravated an ankle injury he'd been dealing with already.

Veteran defensive tackle T.Y. McGill, who had two sacks on Sunday, used Saturday night to further his case for a roster spot. McGill had 1 1⁄2 sacks, nearly posting another one in the second half.

The Vikings, though, gave up 225 yards to the 49ers in the second half, when their own offense ran just 17 plays in the final two quarters.

"Our defense, I just felt like we left them out there on the field too much, even when you're subbing," O'Connell said. "Tonight was about our offense not sustaining enough to give ourselves a chance to win."