Boston Mayor Martin J. Walsh sideswiped state officials yesterday for delays in giving the green light to a first-ever road race on the city’s South Boston waterfront, days before the event could take another hit — losing its marquee spot as the sport’s season finale.

Walsh, clearly frustrated at mounting questions about funding and other criticism surrounding the Boston ?IndyCar race, told the Herald, “I don’t understand” why several state agencies that control roads where the course is planned haven’t signed agreements with race organizers.

“We’re not talking about building a 60-story building in the city of Boston,” Walsh said. “We’re talking about a race that’s going to last for three days, so I’m not ?sure what the confusion is around it.”

The mayor, who signed an agreement with race organizers in May without public input or state approval, also complained that critics and others are making “a big deal … over this” by questioning the impact the race will have on residents and traffic.

Walsh’s comments come as Verizon IndyCar reportedly plans to announce its 2016 schedule next week with Boston’s Labor Day race as the next-to-last event of the season — not the final spot that race organizers and Walsh had promised. A number of racing publications have reported the season finale will be Sept. 18 in Sonoma, Calif.

Walsh had touted hosting the season “championship” race as a major factor in why the event, with turbocharged cars flying up to 170 miles per hour on city streets, would be successful in Boston and generate millions in revenue and 250,000 visitors.

“We were the last race,” Walsh said yesterday, admitting that having Boston in that spot was “somewhat the exciting piece of it.”

The mayor’s role in bringing IndyCar to Boston has made him a target of critics who say the deal was hastily written and could end up costing the city millions — as well as creating public safety risks and weeks of traffic headaches.

The Herald reported earlier this week that the Massachusetts Convention Center Authority, which controls two roads on the proposed race route, was not “anywhere close” to signing agreements to hold the event.

The MCCA’s interim director, Fred Peterson, said that race organizers faced a number of tough hurdles in getting permits for the event, including possible environmental questions over a hazardous waste site under the race course.

Earlier this month, the head of Massport, another agency with control over parts of the IndyCar course, told the Herald he wouldn’t approve any use of public funds for road improvements and other construction.

“They’re going to have to work it out with them and figure it out,” Walsh responded yesterday. “This has been ongoing for a long time now. I don’t understand why it can’t be worked out by now.”

A spokeswoman for the convention center authority said that Peterson would have no response to Walsh’s comments.