However despite Goodell's original optimism, Mara has stated that it may now be too close to the new campaign for changes as big as the one suggested to take place.
He told New York Newsday: "I don't think it's going to happen this year. I think it's kind of late now. I sense that we'll wait a year before we do that and it hasn't been voted on yet.
"The league would notify us in advance, but I'm thinking it's probably not going to happen for another year or so now."
The league's plan is to expand playoff places from 12 to 14, with seven sides from each conference competing in the post-season.
Mara is on the NFL's competition committee, which is made up of 20 team owners from around the league.