Let the real numbers game begin.

On Thursday morning, when the Boston Athletic Association announced an increased field size for the 2014 Boston Marathon, runners around the world undoubtedly estimated their odds of securing a coveted race number. The 2014 event will welcome 36,000 entrants, 9,000 more than this year. But it’s uncertain whether the larger field will fully accommodate increased interest in the historic 26.2-mile race.

Following the bombings in April, many marathoners expressed a desire to enter the 2014 race as a show of solidarity and resiliency. And many scrambled to achieve qualifying times in late spring and summer marathons. The 36,000, a figure short of the record 38,708 entrants in the 100th Boston Marathon in 1996, will be divided among qualifiers, non-finishers from the 2013 race eligible for an early registration period, and special invitations. The special invitations cover charity runners and could include runners with connections to the bombing victims.

Before registration opens Sept. 9 at 10 a.m., the BAA and race organizers will determine the number of slots allotted qualifiers and special invitations. Based on breakdowns from recent races, it’s likely there will be approximately 29,000 race numbers given to qualifiers and 2013 non-finishers. The remaining 7,000 likely will be assigned to charity runners and special invitations. In recent years, the BAA has tried to keep the special invitation/waiver/non-qualified runners around 20 percent of the total field or roughly 5,500 out of 27,000.

The next question is how quickly will qualifiers claim those roughly 29,000 spots. That is the great unknown of the upcoming “rolling admission” period that favors the fastest runners.

Recent marathon results show an uptick in Boston qualifiers. Arlington-based runner Ray Charbonneau compared the 2012 and 2013 results from 10 summer marathons and concluded “that while the number of finishers barely increased from one year to the next, the percentage of runners who qualified increased at a much higher rate” and surmised “it might indicate that those who ran summer marathons were more focused on hitting their [Boston qualifier] time.” Anecdotal evidence from the local running community and comments on websites visited by marathoners support Charbonneau’s thinking.

From his sampling of 10 races, there were an additional 530 qualifiers. It may be far from an overwhelming number, but more interest plus more qualifiers in other marathons could mean registration never reaches a second week.

Registration will be held entirely online at and will proceed on the same schedule as it did for the 2012 and 2013 races until the field size is reached. The registration fee for qualifiers is $175 for US residents and $225 for international runners, a $25 increase. But the higher fee is unlikely to deter qualifiers determined to stand at the Hopkinton start on April 21.

“The BAA is aware of the significantly increased interest in registering for the 2014 Boston Marathon,” BAA executive director Tom Grilk said in a release. “The rolling admission schedule will provide runners with the fastest qualifying times in their age and gender group the ability to have their entry accepted in an orderly and systematic manner.’’

On Sept. 9-10, qualifiers who met their age and gender designated qualifying standards by 20 minutes or more can sign up. Then, if space remains, qualifiers who ran 10 minutes or faster (Wednesday through Thursday), then five minutes or faster (Friday through Saturday) will follow. If there is still room in the field, there will be a second week of registration when all qualifiers can enter.

“Obviously, we don’t know exactly what to expect in terms of how many people who have met the qualifying standard will register, how many are BQ minus 20 minutes, BQ minus 10,” said race director Dave McGillivray. “We’ll be methodically monitoring it, so we know where it’s headed.”

Grilk and McGillivray also methodically monitored the special registration period for non-finishers. Starting Aug. 19, the BAA allowed 5,624 runners who did not have an opportunity to finish the 2013 race because of the bombings a chance to enter early. Non-finishers were eligible for the special registration period if they reached the half-marathon checkpoint or later. At the conclusion of the special registration period at 5 p.m. Thursday, 4,722 had taken advantage of the guaranteed entry.

The non-finishers number is in addition to the 254 runners who also registered this week, earning a spot with their participation in 10 or more consecutive Boston Marathons and a valid qualifying time.

As the field takes more definitive shape, the BAA is reviewing race-day logistics. With 36,000 runners, it’s likely there will be a fourth wave, meaning a more complicated start and finish staging and longer road closures. Organizers may need to stagger runner arrivals in Hopkinton to avoid overcrowding.

For example, Wave 4 may arrive at the start staging area as Wave 1 waits in corrals along Main Street.

Additionally, it’s likely there will be secured areas around the start and finish line open only to runners, credentialed race staff, and media. Those plans are under discussion.

“We’re now considering a fourth wave,” said McGillivray. “We need to work through that process with the town of Hopkinton. Going in that direction means we may need a little more time on the road, but not need more real estate, which we don’t have. Now that the 36,000 has been committed to we’re going to have to figure out how we’ll structure that [start] so it works for everyone.”

For the 100th Marathon, participants awaited the start on land that was Terry’s Farm. Today, land is the new Hopkinton High School.

And the 36,000 runners flooding into Hopkinton doesn’t take into account the potential for more bandit runners, unofficial marathoners without race numbers, than in past years. While running the Boston Marathon as a bandit has been a time-honored tradition for some, increased security at the start will make the endeavor more difficult in 2014. Still, given the post-bombings significance of the 2014 race, Hopkinton will probably be a strong draw for non-qualifiers and qualifiers who may not make the registration cut, even if tighter security measures force them to start somewhere along the course.

“Interested runners have been remarkably respectful and cooperative as we worked towards what will be an important day in the history of the race, the sport, and the City of Boston,” said Grilk. “The BAA offers special thanks and gratitude to the town, city, and state officials for the cooperation and allowances needed to conduct a special race of this size and scope.”

The size and scope of the race may be confirmed, but it is impossible to predict the overall impact. Determining next year’s field size is a big, early step toward shaping what will be an especially historical and emotional Boston Marathon.