Mohegan Sun and Wynn Resorts caught a break Thursday when Massachusetts gaming regulators rejected the city of Boston’s claim that it should be declared a “host community” for casino projects proposed in the Greater Boston cities of Revere and Everett, a designation that would have subjected the plans to referendum votes in Boston neighborhoods.

The Massachusetts Gaming Commission ruled “in principle” that Boston’s status in both cases is that of a “surrounding community.”

The decision, which the panel plans to formalize next week, may have extended the life of the competing projects, since voters in the East Boston neighborhood, which borders Revere, and Charlestown, which borders Everett, likely would reject casino projects.

East Boston voters shot down an earlier project proposed for Suffolk Downs, the horse racing track that straddles the Revere-East Boston line. Soon after the rejection, Suffolk Downs owners teamed with Mohegan Sun, which proposed the Revere-only project the commission considered Thursday.

Revere voters solidly endorsed the original Suffolk Downs project as well as the Mohegan Sun plan. Everett voters overwhelmingly backed Wynn’s proposal.

The commission is expected to award the sole Greater Boston casino license to either Mohegan Sun or Wynn — or neither — this summer. A lawsuit over the commission’s vote Thursday could push back the timetable considerably.

Mohegan Sun officials met Wednesday with Boston Mayor Martin Walsh but failed to reach an agreement on the city’s status in regard to the Revere project. Mitchell Etess, chief executive officer of the Mohegan Tribal Gaming Authority, issued a statement Thursday after the commission’s preliminary vote.

“We remain committed to continuing the productive discussions we’ve had with the City of Boston, and to reaching a comprehensive surrounding community agreement, as we have with eight other neighboring communities,” Etess said. “We also look forward to continuing to work cooperatively with the gaming commission and demonstrating that Mohegan Sun is the best choice for Massachusetts.”

The four seated members of the five-member commission voted unanimously. Commission Chairman Stephen Crosby recused himself. He had been criticized for attending a private Kentucky Derby viewing party Saturday at Suffolk Downs. Earlier, Boston officials had asked that he remove himself from the debate over the city’s status, citing alleged conflicts of interest.

In Crosby’s absence, Commissioner James McHugh presided at Thursday’s hourslong commission meeting. After representatives of Mohegan Sun, Wynn, the City of Boston, the City of Revere and the No Eastie Casino group spoke, McHugh called for what he termed “a preliminary vote.”

Attorney Thomas Frongillo, who represented the City of Boston, argued that the Mohegan Sun’s Revere project is inextricably linked to the Suffolk Downs racetrack, which he said should be considered an amenity of the “gambling establishment.” Most of the track itself is located in East Boston.

Kevin Conroy, a Mohegan Sun attorney, said the proposed casino and the racetrack are separate entities and that Sterling Suffolk Racecourse, the track’s owner, would continue to manage the track.

In the end, McHugh said, the commission was bound by the state gambling law’s definition of “gaming establishment,” which he said is the premises on which the casino is located as well as amenities over which the casino has control.

“The legislation defined ‘host community’ in geographical terms,” he said.

b.hallenbeck@theday.com