This is the third delay to the opening of the stadium, which features a unique retractable roof.
The first event at MBS will now be the Atlanta Falcons' preseason match against the Arizona Cardinals on August 26.
The Aug. 13 and 19 matches will be rescheduled to later dates at Mercedes-Benz Stadium.
Asked what changed in the past week, Cannon said Tuesday that they weren't "100 percent" on the July 30 date as of last week.
"There have been some pretty wild rumors, specifically about the roof's design, it's construction, it's viability. Yes, we have a complex design, we have a complex building but there has never been any concern about the operability of the roof", said Cannon.
He also tried to ease any worries about the stadium construction, saying the revised timeline was due to "normal surveying and analysis of the roof structure, as well as steelwork in the roof".
The new opening date of the stadium is the Atlanta Falcons' August 26 National Football League preseason game against Arizona. The stadium was scheduled to be open March 30, and then June 1, and then July 30 ... and the prospect now looms that there could be further delays.
The Falcons also are scheduled to play host to the Jacksonville Jaguars in an exhibition game on August 31. The NFL regular season schedule has not been announced, but all Falcons home games will be scheduled for MBS.
Alabama vs. Florida State takes place September 2, followed by Georgia Tech vs. Tennessee on September 4 (Labor Day night).
Along with that, Cannon said that the scheduled demolition of the Georgia Dome - located right next door to the new stadium after being cast away at the old age (in stadium terms, apparently) of 25 - will not take place as an "insurance policy" in case the new stadium doesn't get final approval in time for FSU football taking on Alabama.
"We haven't asked the question too often because we know it will be ready by January 8", Hancock said during a visit to Atlanta last week. Initial promotions indicated those seats would be removed from the Dome immediately and shipped to buyers between March 15 and April 15. Cannon would not comment on what other equipment would have to be returned to make the Georgia Dome operational.
"We don't expect to use the Georgia Dome whatsoever", Cannon said on Tuesday's news conference call.
The status of the new stadium was a hot topic at least week's unveiling of Atlanta United's new practice facility. Orlando City on July 30 will be moved to July 29 at their current home of Bobby Dodd Stadium, and will remain on FOX.