It looks like thoroughbred horse racing won’t return to the Brockton Fairgrounds this summer, after all.

Chris Carney, whose family owns the 60-acre fairgrounds, said he is tabling plans to host 15 days of racing after the Massachusetts Gaming Commission denied a portion of a $4.2 million request to support the event.

“I won’t run,’’ Carney said after the vote. “The numbers don’t add up.’’

In a unanimous decision, the commission authorized nearly $3.2 million for the races, but denied about $1 million for racetrack upgrades and other expenses.

“This is taxpayer money,’’ said Commissioner Gayle Cameron. “We have a responsibility to use taxpayer money wisely. It’s not just, ‘Give it all to the horsemen.’ That can’t be how we make a decision, frankly.’’

Brockton organizers had sought to tap into a horse racing fund established by the state’s 2011 casino law for cash prizes awarded to a winning horse’s owner, trainer, and jockey. The fund receives 9 percent of gambling revenue from Plainridge Park Casino in Plainville and a portion of licensing fees paid by casino developers. As of June 30, the fund contained just over $13 million, according to the commission.

The commission approved $2.5 million in prizes, $400,000 for training and stalling horses in Brockton for 16 weeks, and $262,000 in administrative costs for the Massachusetts Thoroughbred Horsemen’s Association, which was helping to organize the races.

Michael Morizio, a lawyer for the Carney family, said his client is not seeking to make a profit on the races, which were scheduled to begin Sept. 5.

Track owners had hoped the fairgrounds would become home to a $677 million casino-and-hotel complex, but the commission voted down the project in April. The Brockton Fairgrounds last hosted thoroughbred horse racing in 2001, Morizio said.

“We’re not trying to make any money,’’ Morizio said. “This is not something that’s to benefit [the Carney] family at all.’’

William G. Lagorio, president of the Massachusetts Thoroughbred Horsemen’s Association, said the races and training in Brockton could create 60 to 90 full-time jobs.

“It’s all about jobs,’’ he said. “We’re saving an industry. We’re saving farms.’’

Robert Scarano, general counsel for the horsemen’s association, said his group may ask the commission to reconsider.

“There’s still a window of opportunity here. I think there’s a way, maybe, to make this work,’’ Lagorio said. “We weren’t completely shut down today.’’

In June, the commission approved $2.4 million to support six days of horse racing at Suffolk Downs. The track held races in July and earlier this month. Another race is planned for Sept. 3-4.

Laura Crimaldi can be reached at laura.crimaldi@globe.com. Follow her on Twitter @lauracrimaldi.