RENTON, Wash. -- Matt Hasselbeck knows of one proven, healthy Seahawks wide receiver still standing.
"Steve Largent," Seattle's quarterback deadpanned Monday, referring to the team's first Hall of Fame player, after hearing the surprising news wide receiver Nate Burleson is out for the season with a knee injury.
An MRI Monday showed Burleson tore the anterior cruciate ligament in his left knee while trying to cut outside on a pass pattern on a rain-slicked, synthetic field in Buffalo on Sunday during Seattle's 34-10 loss in its season opener. The non-contact injury occurred midway through the third quarter when he appeared to trip over his own feet -- or the 20-yard line.
"Tried to plant. Nobody around me at all. I don't know if I got caught in the grass," said Burleson, who caught Hasselbeck's only touchdown pass of the day. "It's tough news -- especially after a loss, man. ... Just one of those things that was meant to happen, I guess. I've got a tough journey ahead."
Burleson joins Deion Branch, Bobby Engram and Ben Obomanu with major injuries at a position where Seattle now has just three healthy bodies heading into this Sunday's game against San Francisco. Coach Mike Holmgren says Branch and Engram remain out indefinitely. Obomanu is on injured reserve.
Branch, a former Super Bowl MVP, is seven months into recovery for reconstructive knee surgery similar to what Burleson now faces. Engram, who set Seattle's record with 94 catches last season, may be out into October with a broken shoulder.
"I was just trying to hold it down until Bobby gets back, until Deion gets back," Burleson said, quietly.
"It's a huge loss," said Hasselbeck, the three-time Pro Bowler who missed almost all of the preseason with a bad back then was 17-for-41 throwing to Burleson and a cast of unknowns Sunday. "And we've got to get some answers."
Holmgren said one may be the stopgap signing of a veteran free agent before practice on Wednesday. The coach also said dynamic backup quarterback Seneca Wallace, who fair caught two punts for Burleson late in the loss to the Bills, "quite possibly" will have a primary receiving role against the 49ers. The Seahawks also may promote from the practice squad rookie free agent Michael Bumpus out of Washington State.
The only healthy wide receivers on the roster are Jordan Kent, a former basketball player and track runner at Oregon, 2007 undrafted free agent Logan Payne and second-year man Courtney Taylor, who has seven career catches and dropped two passes on Sunday.
"It's been a very unusual situation," Holmgren said. "I haven't been in this one -- ever."
And there's more: starting running back Maurice Morris will also miss at least the next two games with a sprained right knee. Former Dallas lead runner Julius Jones will have the starting job at least until Morris returns, with T.J. Duckett as the backup.
"It's not as bad as it could be. A couple weeks," Morris said.
All this is in the wake of Seattle's second-largest margin of defeat in any of its 33 season openers. The offense couldn't run, couldn't catch and couldn't pass block against the Bills.
"I don't think we could be much worse," Holmgren said.
"In any NFL season you are going to face adversity," Hasselbeck said. "It's Week 1, and here it is for us. We're facing a lot of adversity right now."
Burleson's loss was particularly stinging because after Sunday's game he said the injury was minor and he would play against the 49ers. He first felt instability in the knee during the first quarter, but put a protective sleeve on it and kept playing.
"After the game, I was able to put pressure on it. I was able to walk," said Burleson, in his third season with his hometown team following a trade from Minnesota.
As late as Monday morning, before Burleson got further tests, Holmgren thought Burleson would be OK. Then came the MRI showing the ligament tear.
Burleson said he was shocked.
"We were all a little surprised. I think yesterday we left the locker room and I don't think anyone was too concerned," Hasselbeck said. "To get the news today, it was tough to handle."
They have five days to get a grip before the 49ers arrive.