Another star fell for the Seahawks on Sunday, and not the kind on which you can wish.

Losing 31-13 at home to the Minnesota Vikings was only the half of it. The Seahawks lost much more, but for how long won't be known until today at the soonest.

Matt Hasselbeck — quarterback, captain and team leader — suffered a sprained right knee in the third quarter. He never returned after the injury, and the Seahawks fell apart.

"He's going to get pictures [MRI] taken [Monday]," Seahawks coach Mike Holmgren said. "I'm not saying anything about what it is."

Whatever the status, Seattle faces the possibility of playing at Kansas City next week — and perhaps beyond — with neither its starting quarterback nor its MVP running back, Shaun Alexander, who is still out with a cracked bone in his left foot.

Holmgren and the Seahawks tried to paint as rosy an outlook as they could. But the mood in the locker room was somber at best.

"I'm not nervous," Holmgren said. "... With a week of practice, [Seneca Wallace is] expected to go in and play the position well. It is what it is."

Wallace, the Seahawks' fourth-year backup quarterback, fumbled in the end zone and was intercepted twice. That and a couple big plays on offense helped Minnesota turn a 10-10 tie when Hasselbeck was lost into a runaway victory.

Hasselbeck wasn't available for comment after the game. He was taken to the locker room a few moments after being injured.

The injury appeared to be unfortunate circumstance. Hasselbeck had gotten off a pass intended for fullback Josh Parry. Replays showed Hasselbeck standing and watching the throw as Minnesota linebacker E.J. Henderson rolled into his lower leg, crumpling Hasselbeck to the turf in pain.

Seahawks fullback Mack Strong was blocking Henderson on the play.

"I was just blocking him and threw him to the ground, and I thought it was a late hit," Strong said. "He kind of crawled into Matt's leg or whatever. But they didn't make the call, so I'd have to look at the film or whatever."

Henderson saw it differently.

"I kind of ended up on the ground, but No. 38 [Strong] was still pushing me in my back. I tried to turn to the side, you know what I mean?" Henderson said. "I was going to the ground. He pushed me, and I tried to turn to the side to get away from him [Hasselbeck]."

Hasselbeck, who was 7 for 17 for 127 yards and a TD, put no weight on his leg as he was helped off the field. He later walked to the locker room.

Center Robbie Tobeck told Hasselbeck to keep his chin up and get back as soon as he can. The Seahawks can only hope it is very soon.

Hasselbeck connected with wide receiver Darrell Jackson on a first-quarter slant pattern for a 72-yard touchdown, then Josh Brown gave Seattle a 10-3 lead in the second quarter with a 42-yard field goal. But that lead became a 10-10 tie after Minnesota quarterback Brad Johnson went over the top to receiver Marcus Robinson for a 40-yard scoring play.

The third quarter saw the dismantling of the Seahawks. First came Hasselbeck's injury. Then the Vikings marched down the field on their ensuing possession and scored with trickery. Backup running back Mewelde Moore, just before being hit by the Seahawks' Lofa Tatupu, tossed a 15-yard TD pass to Jermaine Wiggins for a 17-10 lead.

Wallace and the Seahawks went without a first down on back-to-back possessions, but a 58-yard Ryan Plackemeier punt to Minnesota's 5-yard line after the second possession pinned the Vikings deep in Seattle territory.

It was to no avail, however, as Vikings running back Chester Taylor effectively sealed the win for the Vikings (4-2) on the first play of the drive.

Taylor started inside, then cut to the left and ran past Tatupu and linebacker Julian Peterson. He broke through a hole near the left sideline.

Safety Michael Boulware had the only shot at catching Taylor, and his last-ditch, dive-and-swipe attempt failed. The run went for 95 yards, the longest run from scrimmage ever allowed by the Seahawks.

"That was the biggest play I've probably ever seen in my professional career on any defense I've ever been on," Peterson said. "He just made a good play, to tell you the truth. Everybody was in the right position. ... He just kind of hid, ducked a little bit, nobody saw him and he got a chance to hit it."

Now the Seahawks are 4-2 themselves and no longer in sole possession of first place in the NFC West. And maybe wishing on a few stars they'll rebound from Sunday.

José Miguel Romero: 206-464-2409 or jromero@seattletimes.com