SEATTLE — The one thing the Seattle Seahawks could not afford is what they got in their preseason finale: another major injury at wide receiver.

T.J. Duckett showed he may be more than just the short-yardage back coach Mike Holmgren thinks he is by running for 71 yards and two touchdowns, but Seattle lost versatile receiver Ben Obomanu to a broken clavicle in a 23-16 victory over the Oakland Raiders on Friday night, a game without all but three starters.

“That’s a tough one, certainly,” Holmgren said, adding the third-year veteran could possibly go on season-ending injured reserve when final roster cuts are announced Saturday. “He was very much a part of our plans.”

Obomanu was injured in the first quarter on a 33-yard pass from Seneca Wallace. It set up a 34-yard field goal by Olindo Mare that made it 10-0.

Seattle is already without Bobby Engram. The team record-holder with 94 catches last season may be out into October with a broken shoulder. And former Super Bowl MVP Deion Branch is just seven months into rehabilitation from reconstructive knee surgery. He may test his knee next week to see if he can play in the season opener Sept. 7 at Buffalo.

Holmgren said Obomanu’s injury means Michael Bumpus, the undrafted rookie from Washington State who caught three passes for a game-high 53 yards, has joined “that mix” with former University of Oregon basketball player Jordan Kent, 2007 practice-squad player Logan Payne and Courtney Taylor for a final roster spot at receiver.

Seahawks Pro Bowl quarterback Matt Hasselbeck was in sweats to rest a back that has been tight since Aug. 8. He will start the opener having played just two snaps since last January’s playoffs.

Wallace, slowed this month by a groin injury, was 21-of-30 for 225 yards in Hasselbeck’s place. Wallace fumbled away a scoring chance at the Raiders 3 while getting sacked in the third quarter.

Oakland starter JaMarcus Russell, who will start the Sept. 8 opener against Denver, was in uniform. But the No. 1 overall pick in 2007 stayed on the sideline wearing a team coat as Andrew Walter concluded an improved preseason. Walter was 16-of-24 for 162 yards before yielding to hometown veteran Marques Tuiasosopo with 9:26 remaining.

“Very successful on the first thing: nobody got hurt,” Raiders second-year coach Lane Kiffin said.

Tuiasosopo, who led Washington to the 2001 Rose Bowl, threw a 25-touchdown pass to former Huskies receiver Marcel Reece with 1:51 left.

The only starters appearing were Seahawks (3-1). Center Chris Spencer played the first two series, his first game since last January’s playoff loss at Green Bay following surgeries on his shoulder and thumb then a back injury last month. Regular right guard Rob Sims started next to him.

On defense, rookie first-round pick Lawrence Jackson started at right end.

It wasn’t that the reserves weren’t impressive.

In the second quarter, Darren McFadden showed why he was the fourth overall draft pick by Oakland, a finalist for the Heisman Trophy and the star of training camp, according to Kiffin.

McFadden took a handoff, stopped behind traffic on the right, veered left, ran through an arm hug from Seattle’s Jason Babin and bolted up field. McFadden appeared on his way to the end zone before Josh Wilson grabbed his shoe and tripped him for a 23-yard gain that brought gasps from the crowd.

McFadden finished with 50 yards on four carries. He will begin the season as the No. 2 back behind Justin Fargas.

Asked if that was a glimpse of what McFadden can do, Walter said: “Absolutely. You see it every day in practice, but when you see it out there in the game ... he looked great.”

Oakland (1-3) got a scare — and the rest of the stadium got a laugh — when Pro Bowl punter Shane Lechler dropped a high snap from Jon Condo on a 21-yard field goal try by Sebastian Janikowski in the first quarter. Lechler, a high school quarterback who wasn’t punting because of a quadriceps injury, ambled away and launched a shot-put toss that C.J. Wallace intercepted and returned 41 yards.

Broncos 28, Cardinals 14

GLENDALE, Ariz. — Third-string quarterback Darrell Hackney threw for 208 yards, including an 87-yard touchdown to Keary Colbert, and Denver beat Arizona 28-14 on Friday night in the preseason finale for both teams.

Hackney’s long pass to Colbert put the Broncos (2-2) up 21-14 with 8:51 remaining. Denver’s Jack Williams picked off Anthony Morelli’s pass and returned it 87 yards for a score with 5:42 to play.

Matt Leinart relieved starter Kurt Warner and directed the Cardinals (2-2) to two touchdowns. He was 10-of-14 for 177 yards and a score, all in the second quarter.

Warner was 4-for-4 for 48 yards but couldn’t get Arizona on the scoreboard.

Twenty-nine Denver players sat out the game, as is the custom for the final preseason contest for coach Mike Shanahan.

Chargers 20, 49ers 17

SAN FRANCISCO — Eldra Buckley made a one-armed diving catch on a 2-yard touchdown pass with 29 seconds left for San Diego.

Third-stringer Charlie Whitehurst passed for 144 yards and Malcom Floyd had six catches for 68 yards for the Chargers (3-1), whose best players all sat out the club’s second exhibition game in five days.

Alex Smith, who lost the 49ers (2-2) starting quarterback job to J.T. O’Sullivan, passed for 146 yards but threw two terrible interceptions.

O’Sullivan and Frank Gore sat out along with linebacker Patrick Willis, defensive end Justin Smith and cornerback Nate Clements, but receiver Bryant Johnson looked good in his first limited action with San Francisco, catching three passes for 41 yards in his late bid to keep a starting job.

Hobbled Chargers linebacker Shawne Merriman was in uniform during warmups, but he joined LaDainian Tomlinson, Philip Rivers, Antonio Gates, Chris Chambers and Jamal Williams on the sideline when the game began.