By Miranda Morgan, World-Track
It was suggested that a fast race between himself and Jeremy Wariner could see the record lowering.
Merritt, however, despite staying optimistic, thinks for someone to challenge the 43.18-seconds world mark of Johnson set in 1999 they will have to run low 43-seconds consistently.
"I don’t really see it this year," the American said at the press conference for Sunday’s Prefontaine Classic Grand Prix meeting in Eugene. "But if it happens, it happens.
"Somebody is going to have to be running under 43.5 consistently to really break the world record this year."
Merritt has started the season impressively – running 20.07sec for the 200m and 44.50sec for the 400m and he is hoping to build on those performances.
He added that he is satisfied with the progress he has made this campaign and is looking for to having another fruit year.
"Training has been going well, I feel strong mentally and physically, so I’m planning on have a good year," he said.
"I’m trying to pick up this year where I left off last year. In 2007 I ran 43.9 and last year I ran 43.7, so each year I am getting a little better.
"I am planning on dropping my time this year when it really counts.
"I am planning on going to nationals, do what I have to do and (also) looking forward to the European circuit and winning at Berlin
Merritt said his dominant victory last year over a very strong line up at the Beijing Games, has helped him to grow.
"It makes me strong mentally," he said. "It lets me know that I can perform at the big stage.
"It doesn’t get any bigger than winning at the Olympics in this sport….going to the finals and dominate and did what I went there to do."
At Prefontaine Merritt will star favourite to win the men’s 300m dash. He said he is hoping to run faster race to shape this up for his next event in Toronto on June 11.