Defensive ends Floyd and Gross-Matos injured

The 49ers took a risk in Las Vegas by using top players in the final game of their preseason, but that strategy quickly backfired as injuries occurred at a top position that offered little depth.

Defensive ends Leonard Floyd and Yetur Gross-Matos, two of their most valuable free agency signings, limped off the field with knee sprains in the first quarter of Friday night's 24-24 tie against the Raiders.

A tear in the anterior cruciate ligament was also not detectable, and MRI scans on Saturday should provide information on whether her ability to play in the opening game of the regular season on September 9 is in question, coach Kyle Shanahan told reporters afterwards.

Shanahan said it was “not a good feeling” to see those injuries, but he knew the risk of putting key players — but not star defensive end Nick Bosa — on the same field where the 49ers lost Super Bowl LVIII six months ago. (Yes, they failed to hold on to a 3-point lead in the final minutes in that game either; there is no overtime in the preseason.)

On offense, Deebo Samuel and George Kittle made their preseason debuts as productive targets for Brock Purdy — and that trio seemed to be injury-free. “It felt a little bit like last year when our guys were on the field and making plays,” Purdy said on the CBS-5 broadcast during the third quarter.

Another offensive star was surprisingly present, albeit not in uniform: Brandon Aiyuk, who had traveled with the team and mingled with the crowd on the field before the game, although there was no official report of a breakthrough in his contract negotiations.

The special teams also made their presence felt. First, the Raiders managed an 81-yard punt return in the second quarter for a touchdown. The 49ers countered when rookie speedster Isaac Guerendo, in his debut, made a 93-yard kick return that broke all tackles and gave the 49ers a touchdown that gave them a 17-14 halftime lead.

Double blow due to injuries

The loss of two defensive ends within three snaps was the most astonishing sequence.

Gross-Matos, who started because Bosa was certain to miss another preseason, injured his knee when linebacker DeVondre Campbell made a tackle early in the defense's second series. Two snaps later, Floyd's right knee was injured on the pass rush when he collided with Maliek Collins with 2:06 left in the first quarter.

Floyd was the 49ers' most successful signing this offseason. He hasn't missed a game in six seasons, so the 49ers are now really banking on his consistency as a pass-rushing opponent to Bosa. Gross-Matos quickly established himself as the third defensive end.

Purdy said of Floyd in his post-game press conference: “They say he's getting better. Hopefully he's fit. It's always scary when we see one of our regular players out in the third preseason game.”

It's a position where the 49ers already had 2022 top pick Drake Jackson out for the season with a knee injury. Robert Beal Jr., Alex Barrett, Sam Okuayinonu and Jonathan Garvin are their other defensive ends ahead of Tuesday's 53-man roster deadline. Okuayinonu made a last-minute sack.

PURDYS PERFORMANCE

Those injuries preceded the 49ers' third offensive series — and the last one featuring Purdy, Kittle and Samuel. Purdy scored on the first two possessions and was close to scoring more until he threw an interception in the red zone on a fastball that Samuel couldn't catch in tight coverage.

Purdy (9 of 12, 96 yards) opened with a one-pump, 27-yard catch to a running back Samuel down the left sideline, then followed with a 15-yard pass over the middle to Kittle, setting off another drive that culminated in a 47-yard field goal by Jake Moody.

As he did twice in his first outing in the first quarter of Sunday's season win over New Orleans, Purdy was again knocked to the turf and on his throwing shoulder twice. Charles Snowden was first when Purdy escaped a slot corner blitz on the first series, and Purdy was thrown again after completing a 15-yard rollout pass to Chris Conley. Further punishment came from a sack when the defense broke down between left tackle Jaylon Moore and left guard Nick Zakelj, who started in place of Trent Williams (contract out) and Aaron Banks (pinky surgery).

“Getting hit is part of the game and you have to feel it,” Purdy said on CBS-5.

He also risked his body by running 14 yards to the Raiders' 17-yard line, bringing back memories of a third-down run that helped the 49ers to a comeback win in the NFC Championship Game against Detroit. That second drive of the series on Friday night ended with a touchdown run by Jordan Mason, and like his touchdown in the season opener at Tennessee, Mason was pushed over the goal line by Dominick Puni, the 49ers' rookie starter at right guard.

AIYUK APPEARS, SITS OUT

AIyuk entered Allegiant Stadium with Samuel but did not change clothes or participate in warmups. Chris Conley started in Aiyuk's place across from Samuel. Aiyuk did not attend Tennessee's season opener two weeks ago and sat in a suite to watch Sunday's home win over New Orleans.

Also not used in any of the three preseason games were running backs Christian McCaffrey (calf) and Elijah Mitchell (thigh), fullback Kyle Juszczyk, defensive end Nick Bosa, linebacker Fred Warner and cornerback Charvarius Ward as well as Aiyuk and left tackle Trent Williams due to contract issues with the latter two.

Williams' walkout cost him an additional $1.1 million on Friday – the equivalent of a check for a regular-season game – bringing his total fine to $4.15 million, which cannot be reduced or waived under the NFL's collective bargaining agreement for a contract signed as a free agent.

GUERENDO'S PROFESSIONAL DEBUT

Guerendo played as advertised: a fourth-round draft pick with unmatched speed. That goes beyond his 93-yard kick return in the second quarter. He returned the game's opening kickoff 29 yards. Two consecutive 6-yard runs in the red zone set up Mason's touchdown for a 10-0 lead. He later converted a short run for a 3-yard gain. It was his 93-yard return that set up a 1-yard touchdown run by Patrick Taylor Jr., who broke a backfield tackle after a bad block by Cam Latu.

PEARSALL'S STATUS

Also conspicuously absent throughout the preseason was wide receiver Ricky Pearsall, the 49ers' first-round draft pick. A torn hamstring delayed his entry into training camp, and after a week of practice, his shoulder injury worsened, lasting at least until spring training after the draft.

San Francisco Chronicle columnist Mike Silver told KNBR-680 AM that Pearsall “has a shoulder problem that's recurring now and that's a concern in the long run. They knew about it before they signed him and hoped it wouldn't happen.” Pearsall has been practicing on the sidelines for the past few weeks and this week he showed impairment while casually throwing a football and playing catch.

Shanahan clarified after the game that Pearsall had suffered a subluxation – a partial dislocation – of his shoulder.

“He did it in college, I think his third year. About 50 percent of guys coming out of college do that,” Shanahan said. “That really wasn't the issue. He did it for the first time at OTAs with us,” Shanahan said, referring to spring training in May and June. “When you do that, it's sensitive. And then he did it again here a couple weeks ago. That makes it sensitive, so you want to give him time to recover from that.”

GAME NOTES

– Passing specialist Klay Kubiak called plays for the third time in as many preseason games, replacing Kyle Shanahan. Shanahan said last week that he will be back as a playmaker in the season opener on September 9, when the New York Jets visit Levi's Stadium.

— On Floyd's first series in a 49ers uniform, he made a third-down stop on quarterback Nathan Peterman, setting up a three-and-out opening series. Collins and Gross-Matos also wore 49ers uniforms for the first time.

— Brandon Allen relieved Purdy and completed 5 of 7 passes for 60 yards with two sacks. Josh Dobbs (5 of 7, 60 yards) entered the game midway through the third quarter before rookie Tanner Mordecai received the bullpen call with six minutes left.

— Rookie Malik Mustapha made his debut in the starting lineup in place of George Odum, who played almost all of the first-team game in training camp; Talanoa Hufanga is on the physically unable to perform list and could remain there for at least the first month of the season unless the 49ers unexpectedly accelerate his comeback in the next two weeks of practice.

— The game ended with an incredibly entertaining play: The Hail Mordecai. Trent Taylor caught a 46-yard pass at the 9-yard line. Here's how the playbook described it: “T.Mordecai plays a deep pass right to T.Taylor to LV 9 for 46 yards. FUMBLES, touched at LV 10, recovered by SF-S.Gutierrez at LV 14. S.Gutierrez to LV 14 for no gain. FUMBLES, recovered by SF-R.Bell at LV 15. R.Bell to LV 22 for -7 yards. Lateral to C.Schrader to LV 23 for -1 yards. FUMBLES, recovered by SF-T.Mordecai at LV 23. T.Mordecai to LV 32 for -9 yards. PENALTY to SF-T.Mordecai, illegal forward pass, 0 yards, enforced at LV 32.” (It appeared Mordecai's second pass to Cody Schrader may have actually been caught as a lateral (thrown at Vegas 33, caught at Vegas 33), and then the ball was thrown to Sebastian Gutierrez, who rumbled toward the end zone before dropping the ball and Jarrett Kingston recovered it near the goal line as the play — and the preseason — was whistled off.)