The 34-year-old Marshall is still returning from the ankle injury that ended his 2017 campaign after just five tilts. He also underwent toe surgery.
The veteran receiver is trying to prove he has enough left in the tank to contribute on the field in his 13th season.
"I'm that guy, I'm that aging football player, right?" he said Thursday, via the team's official website. "So many years, I sat back and watched guys say, 'Yeah, I got something left in the tank.' It's either you got something left in the tank or you don't. I mean, quarter tank, whatever. If you don't got a full tank, then you can't play this game so I'm working my tail off to get 100 percent healthy and get out there and contribute in a major way. I'm not here to just be a guy. I'm here to be the beast that I've always been. I'm confident I'll be able to do that in the next couple weeks."
Marshall didn't exactly look like a world-beater before his season-ending injury last year. He struggled to create a connection with Eli Manning, had a drops problem and created almost no separation from defensive backs.
The aging veteran hopes that his work to get healthy will pay off in 2018.
"I'm not going to lie to you guys, man," Marshall said. "Rehabbing can be a really challenging situation and this was one of the toughest things I've ever been through as an athlete. One, you got the 'I'm aging' part out there, and you got the self-doubt and self-talk creeping in. Then, production slips. You get cut. There's so much negative stuff happening while you're lying on the table trying to be able to walk again. So, yes, it's very difficult and the only thing that gets you over that hump is actually doing it and making those plays that you made in the past."
On virtually every other roster, Marshall would be a prime veteran cut candidate given his low contract guarantee and injury past. With the Seahawks needing playmakers at the position, however, he's landed a chance to make the roster and push for playing time.
Now Marshall must prove he's got enough gas left in the tank for another go-around. Getting on the field for team reps is the first step.