Boston Globe reporter Albert Breer recently interviewed Marshall about playing for a new team after four turbulent seasons with the Denver Broncos.
"It will be the biggest year I've ever had," Marshall said. "As far as wins and production, it's going to be a big, big year. The best year I’ve had so far."
Marshall added a championship is "more than doable."
Marshall, 26, got married over the offseason and claimed he has settled down considerably compared the person "Outside the Lines" profiled 13 months ago because of repeated allegations of domestic violence. He also has been charged with DUI and was involved in the altercation that preceded Broncos teammate Darrent Williams being shot to death.
"It just seems like things in life are simplified," Marshall said in Breer's story. "It's more calm, and I'm excited about that. It's giving me a chance to grow as a person and in my career. I'm excited to have a fresh start on this Miami Dolphins team.
"I'm not worrying about my contract, and that makes it easier to go to work and do my job and help the team. And my home life is very good. I’m happy, and that makes it easier all the way around.
"You know what they say: Happy wife, happy life."
Marshall praised the Dolphins' organizational approach under head coach Tony Sparano.
"It's football, football, football," Marshall said. "The organization is all about football. All that other stuff that comes with being in the NFL that can get in the way, it doesn't happen here."
"We've got a coach that's probably one of the most passionate in the game, a team that's fairly young and wants to win now. Even in the weight room, you see that passion. It carries over everywhere. We can do great things."
Marshall's words come off as strange shots at his previous coaches, Mike Shanahan and Josh McDaniels. Shanahan has won Super Bowls. It's hard to imagine McDaniels, a Bill Belichick protégé, not being passionate about preaching football first.
"My time in Denver was great," Marshall said. "I was surrounded by a great group of guys. But I'm going to say that I never had a chance to go through an offseason where the guys spend every day together on the field and off. We really are one."