Following the game, Smith told reporters he "came out OK," but wouldn't get into any specifics regarding his knee.
Head coach Pete Carroll added the QB might be sore for the next couple days and will "need the break," as Seattle has an early bye to get healthy before facing the Bengals on Oct. 15.
Smith sustained the injury after catching his own batted pass in the second quarter and trying to escape the pocket around the end. Linebacker Isaiah Simmons jumped on Smith's back to bring him down, causing the QB's legs to twist awkwardly underneath him.
With a third-and-13 waiting, Smith initially went to the sidelines, but he re-entered and began jawing with Giants defensive back Xavier McKinney.
"I don't know, honestly," the Pro Bowler said when asked if he thought the tackle should've drawn a flag. "I try not to think about those things. In the moment, I was kind of heated. But after the fact, I don't know."
His head coach was a tad more expressive.
"It just looked so dangerous," Carroll said. "All of the effect of a horse-collar tackle happened with the swing of the body that pulls down on the back of the leg, and he got hurt on that play. A penalty wouldn't have rectified that, but it just looked like such a dangerous play, it might have warranted a second look."
Smith had trouble moving on the next snap and nearly threw a side-armed pick to Kayvon Thibodeaux. It fell harmlessly to the turf, but Smith spent New York's next drive in the blue medical tent and didn't return for the remainder of the frame.
He wasn't the only big-name Seahawks player to contend with an injury Monday night, either. Safety Jamal Adams suffered a concussion nine snaps into his first game since Week 1 of last year and was ruled out.
Smith was 9 of 11 for 67 yards and a touchdown at the time of his exit. Drew Lock entered in relief with Seattle in the lead, 7-3, and extended the margin with a touchdown drive before Smith came back.
The lead only continued growing for the Seahawks from there, as the defense pitched a second-half shutout, added seven more sacks to bring its nightly total to 11 and rookie phenom Devon Witherspoon turned New York's lone red-zone trip into a 97-yard pick-six.
Given such defensive dominance, Smith didn't require any heroics to maintain the win upon his return.
He finished with 109 yards and the aforementioned score on 13-of-20 passing. Much more importantly, he's set to travel back to Seattle victorious and apparently unscathed.
"Ugly situation," Smith said. "But I feel a lot better."