MINNEAPOLIS—The Seahawks headed back to Seattle with a few injury concerns following Sunday night's 25-19 loss to the Vikings.

Three players—safety Marquise Blair, quarterback Paxton Lynch and offensive lineman Demetrius Knox—all left the game with injuries, while rookie receiver DK Metcalf didn't play because of a knee injury that will require surgery, though the hope is that he'll be back soon. 

"DK's got an injury to his knee that we found, it happened two days back," Seahawks head coach Pete Carroll said after the game. "So it's something we've got to do some work on, probably Tuesday, and get him back in a hurry. We're disappointed for him, because he was off to a fantastic start, but I don't think this is going to derail him for long. But he does have to have some work done. We'll know more about that when we get back into town."

Asked the reason for his optimism for a quick return for Metcalf, Carroll said, "The docs really have a clear look at the MRI already, what it is, and it's a really quick recovery. That still all has to happen, we're going to keep him in town and get the work done right away, and be very optimistic about the way he can get back."

As for a potential return by Week 1 of the regular season, Carroll said, "There's optimism reigning about that, yeah."

Blair, who was carted off the field in the second half, was battling back spasms, Carroll said. 

"He had back spasms in the second half," Carroll said. "So I don't know what that means, but he had a play and his back got tight, and it kept getting tighter and he couldn't go back."

Lynch, who relieved Russell Wilson after two series, took a nasty hit to the head—one that got Vikings cornerback Holton Hill ejected—and was taken out of the game, and will now have to clear the concussion protocol before returning to action.  

"He went through the protocol, and he's still in there now," Carroll said. "He felt like he was OK, but he's still got to pass those tests, so we'll recognize all the process and take care of that."

Knox, an undrafted rookie out of Ohio State, had to be carted off with a leg injury Carroll indicated was serious.

"It looks like he's got a quad injury that's involved with the knee area," Carroll said. "It's a nasty injury for him. We've got to do some tests, but it's a quadriceps-related injury in regards to his knee."

Linebacker Shaquem Griffin was held out of the game with a knee injury that limited him in practice last week.

"He had a knee that he came back from that just kind of got reaggravated," Carroll said. "It started with a bruise, and that's what I know about it right now."

Second-year offensive tackle Jamarco Jones did return to practice this week, but wasn't ready for game action yet.