With two of the biggest endurance races in the world kicking off the Tudor United SportsCar Championship next year, it’s no surprise there’s been a significant level of interest from teams both domestically and abroad for the Rolex 24 at Daytona and Twelve Hours of Sebring.

But will they all fit?

That’s something many people are beginning to question, as the GRAND-AM Rolex Sports Car Series and American Le Mans Series seasons draws to a close.

Based on teams’ current plans, full-season entries are projected to reach well over 50 cars. Combined with a likely influx of European teams in both the Prototype and GT Le Mans categories, the season opener is almost certain to feature a capacity field.

It’s a good problem to have, according to USCC President and COO Scott Atherton, although he admitted there may not be room for everyone wanting to take part in the historic opening two rounds of the unified sports car championship.

“You’ll see a similar arrangement there to what has been the case with the ALMS. Full season commitments do take precedence,” Atherton told Sportscar365. “It doesn’t mean we discourage single-event entrants.

“Somebody from Europe, especially coming in to run the Rolex [24] or Sebring, or to do both, we would very much encourage that. But if we do find ourselves in an oversold situation, the priority would be given to our full season competitors.”

Atherton, along with Scot Elkins, IMSA’s Vice President of competition and technical regulations, would not be drawn on an exact number, but the days of having 70-car fields are over, as teams will not share space on pit lane on the grounds of safety.

The grid size will be determined by the number of pit boxes that can be accommodated, which Elkins says would likely limit the field at Daytona to no more than 60 cars. This year’s Rolex 24 featured a 57-car starting field.

“It’s going to be similar to what we’ve had in years’ past,” Elkins said. “We’re just now going through the process of establishing what a pit box size is, how many stalls we can put at a particular venue and working through that.

“In ALMS, we always did it a little bit differently because we always had a penalty box that was separate. GRAND-AM doesn’t do that so we’re trying to work out how we’re going to structure that. Obviously that affects the pit lane lengths.”

The growing concern appears to be whether any one-off entries, or even those committed to the expected four-round North American Endurance Championship would be able to race at Daytona, as well as Sebring, which was capped off to a 63-car car entry last year.

Aston Martin Racing has already confirmed intentions of entering at least one GTE-spec Vantage V8 in the GT LM category for the two enduros, having kept one of its five factory cars in America following the COTA round to take part in pre-season testing.

Fellow WEC competitor AF Corse is also seriously evaluating a partial season program, while there are no fewer than a half-dozen LMP2 teams from Europe have expressed interest in coming to Daytona and/or Sebring.

However, depending on the number of full-season entries, there may not be any room for them.

“The thing is that we want to be supportive of people that are supportive of us,” Elkins said. “So people that commit to the full season, you obviously have to ensure that those folks have spots in the bigger races. We’re having some meetings this week, trying to finalize a lot of things and that’s on the list.”