The 29-year-old notched over 1,000 total yards for the Saints last season despite sharing his carries with the club's other backs.
He believes that he has to always be at his best because of the competition at his position.
Thomas told The Advocate: "I'm still there, up there on the top level with some of these guys. I'm not dropping the ball, I'm not fumbling, I'm not out here getting negative yards.
"I'm always getting positive yards, always doing positive things on the field. It shows. I stay level-headed out here, focused, making sure I do what I have to do. Because every year, every day, I have to fight for my job."
The Saints reached the divisional round of the playoffs last season before being defeated by the eventual Super Bowl champions the Seattle Seahawks.