Springfield, Mass. — MGM Resorts International executives assured city officials here Wednesday that they’re not backing away from MGM Springfield, their downtown resort casino project, and are, in fact, recommitting themselves to it.

Bill Hornbuckle, the MGM Resorts president, announced that his company was upping its investment to more than $950 million from the original $800 million.

“We’re as proud of this project today as we were in September 2012,” when it was first proposed, Hornbuckle said, addressing an audience at CityStage, a downtown venue where residents filled a 479-seat theater.

He later said he would stake his reputation and his career on the project.

In recent months, design changes characterized by some as a downsizing had raised questions about the viability of the project. In particular, the elimination of a 25-story hotel tower and a 14 percent reduction in overall square footage had caused alarm in a city counting on the project’s promise of jobs and revenue.

Hornbuckle said the changes had to be made “for all kinds of reasons” and that they would result in a better project.

Mike Mathis, the MGM Springfield president, said MGM would meet all terms of the “host community agreement” it reached with the city, among them guarantees of $25 million in annual payments, 2,000 construction jobs and 3,000 permanent jobs once the project is built.

He noted that the promised 250 hotel rooms were being preserved in the new design, which calls for a six-story, “street-side” hotel that he said is more in keeping with the overall project’s integration with the downtown area.

“It distinguishes us from the Foxwoods and Mohegan Suns of the world,” Mathis said of the low-rise design.

A residential component of the Springfield project — 54 market-rate apartments — is being moved from within the project’s footprint to an off-site location. Many of the units are to be developed in a former school building.

The changes would actually result in more space devoted to retail and entertainment, MGM officials said, while “back-of-the-house” space and a parking garage would shrink.

“We lost five bowling lanes,” Hornbuckle said, referring to a modest alteration.

In explaining the huge increase in the budget for the project, Hornbuckle said it reflected the escalating cost of goods, services and labor in the region. Originally, he said, project costs that included capitalized interest and land acquisition were expected to exceed $860 million “in 2012 dollars.”

Spending on the project will continue into 2018, he said, with the casino to open in September of that year.

MGM already has paid more than $23 million in construction costs, including demolition, according to Brian Packer, MGM Resorts’ vice president of construction and development.

The company’s presentation appeared to play well with Springfield officials, who have to approve the design changes, as must the Massachusetts Gaming Commission.

Mayor Domenic Sarno said he was satisfied with the state of the project.

“This is a much better design,” he said, citing, in particular, the dispersal of the residential units. “This was nuts-and-bolts stuff, but I wanted the discussion to be public to put to rest some of the misinformation that’s out there. It was important to clear the air.”

Sarno said he was not concerned that the elimination of the hotel tower would hurt the project’s visibility.

“Through signage there are plenty of other ways,” he said. “I’m not worried about people seeing it from I-91.”

Southeastern Connecticut’s casino-owning Indian tribes, concerned about MGM Springfield’s impact on Foxwoods Resort Casino and Mohegan Sun, are pursuing a plan to develop a third Connecticut casino in the Hartford area. MGM Resorts has filed a federal lawsuit that seeks to block that effort.

Hornbuckle, asked about MGM’s interest in developing a Connecticut casino, said that if Connecticut’s legislature allowed such a development, “We’d take a look at it.” MGM’s license for the Springfield project prohibits it from developing another casino within 50 miles of Springfield.

Bridgeport, a Connecticut city outside that range, has been mentioned from time to time as a potential casino site.

b.hallenbeck@theday.com

Twitter: @bjhallenbeckc