Vikings coach Kevin O'Connell said this week that joint practices for many teams have all but replaced preseason action.

Following two joint sessions against the 49ers at TCO Performance Center, O'Connell sat nearly every projected starter during Saturday night's 17-7 preseason loss at U.S. Bank Stadium.

Every starter on offense watched from the sideline — quarterback Kirk Cousins, running back Dalvin Cook, receivers Justin Jefferson, Adam Thielen and K.J. Osborn, left tackle Christian Darrisaw, left guard Ezra Cleveland, center Garrett Bradbury, right guard Jesse Davis and right tackle Brian O'Neill, and tight ends Irv Smith Jr. and Johnny Mundt.

Much of the starting defense also took a seat in edge rushers Danielle Hunter and Za'Darius Smith, linebackers Eric Kendricks and Jordan Hicks, defensive tackles Dalvin Tomlinson and Harrison Phillips, cornerbacks Patrick Peterson, Cam Dantzler and Chandon Sullivan, and safeties Harrison Smith and Cam Bynum.

"Those starters got a lot of work, and a lot of great, competitive work," O'Connell said. "Kirk had a really good week of practice against a really good defense, really good front that consistently gets pressure."

The only projected starter to play was defensive lineman Armon Watts, who has lined up with the first-team defense in its base 3-4 personnel throughout training camp.

Four injured Vikings were sidelined in tight end Irv Smith Jr. (thumb) receiver Dan Chisena (leg), guard/center Chris Reed (elbow) and defensive lineman Jullian Taylor (hand).

The 49ers also rested most starters, including quarterback Trey Lance, tight end George Kittle, receivers Deebo Samuel and Brandon Aiyuk and defensive end Nick Bosa.

Rookies start; Booth injured

The rookie class, including five starters in safety Lewis Cine, corners Andrew Booth Jr. and Akayleb Evans, guard Ed Ingram and linebacker Brian Asamoah, shared growing pains and big moments.

Cine, the 32nd overall pick, was in tight coverage when he watched San Francisco quarterback Nate Sudfeld thread a 19-yard pass to tight end Tyler Kroft. Booth, the second-round pick, aggravated an ankle injury in the second quarter and did not return.

"Aggravation of an injury that we know about already," O'Connell said. "Would love to still get him some work throughout this week as we continue to prep. We'll see where he's at."

Evans, the fourth-round pick, was heavily involved in run support, leading all defenders with nine tackles and a forced fumble. He had a tackle for a loss on fourth down, which he credited to Cine's pre-snap direction.

"He was telling me, 'Get down,'" Evans said, "because he was predicting the run, so shoutout to him."

'Got to be better'

Receiver Ihmir Smith-Marsette remained a volatile option at punt returner. He failed to corral one that bounced and rolled out of bounds for a 56-yard punt. He then fumbled on a return in the second quarter. Smith-Marsette, who had four catches for 27 yards, had his longest return go 14 yards.

"I'm getting acclimated to it," Smith-Marsette said. "They're giving me a shot out here and I got to get it done. I got to be better."

Punters Jordan Berry and Ryan Wright alternated punts as they continued the preseason competition.

Etc.

  • Journeyman defensive tackle T.Y. McGill Jr. has 3.5 sacks in two preseason games after taking down 49ers quarterbacks Brock Purdy and Sudfeld for 1.5 sacks in the second quarter. McGill, 29, is on a ninth NFL team in his eighth season.
  • Defensive coordinator Ed Donatell called plays from the sideline during his first game at U.S. Bank Stadium. Linebackers Troy Dye, in the first half, and Chazz Surratt, in the second half, relayed those play calls in the huddle.
  • The 49ers lost two players to injury: receiver Austin Mack (hamstring) in the second quarter and tackle Sam Schlueter (knee), the Gophers product, in the fourth quarter.