The race is schedule to begin at 12:45 p.m. Eastern time, about 20 minutes later than last year.
Boles was asked about an earlier start to get the race in ahead of possible rain. The Masters golf tournament took that dramatic step for the final round earlier this year.
Boles said such a move is unlikely. He also said the latest the race could start would probably be 6 p.m. because sunset is at 9:02 p.m. The track does not have lights.
NBC will broadcast the iconic Indianapolis 500 this weekend for the first time.
After airing every Indy 500 from 1965 through last season, ABC was outbid for the rights by NBC, giving the network exclusivity over the IndyCar Series.
NBC's "Today" took the show to the Indianapolis Motor Speedway as part of its salute to "Hidden Heroes," those people at home who provide help to America's veterans.
Savannah Guthrie and Al Roker were joined by actor Tom Hanks and former Sen. Elizabeth Dole, who has done extensive work with the Hidden Heroes campaign. Sheryl Crow performed on the front stretch.
Asked why the campaign is important, Hanks told The Associated Press: "Because we're always talking about caregivers, you make an assumption that means experts, medical technicians, doctors. But when we talk about these hidden heroes, we're talking about moms and dads, wives and girlfriends, grandparents. Caregivers that are just like you and me."
Hanks said it was his first trip to the Speedway.