The addition of promotion and relegation in the top professional leagues in the United States could be a major boon for the sport on several fronts, according to a business study by Deloitte.

The study concludes that promotion and relegation between MLS and the lower divisions, NASL and USL, could lead to added interest in the growing U.S. soccer market, better attendance for all leagues involved and improved player development from America's youth programs and clubs.

Deloitte, a consulting firm, was commissioned to create the study by Silva International Investments, led by Riccardo Silva, who also owns Miami FC, a club in the second-tier NASL that currently has no path to move into the top division, as defined by U.S. Soccer.

"The report was paid for by an owner of an NASL club who has a vested interest in promotion. I think that that causes a series of questions about it's credibility," MLS deputy commissioner Mark Abbott told ESPN FC.

Fans are moderately in favor of the idea, according to a poll used in the study that questioned more than 1,000 soccer fans in the U.S.