With just over a week left to meet the requirements set for a mid-September debate in Houston, ten Democratic candidates have already qualified for the ABC News-Univision event, with two more hopefuls on the cusp of being eligible, raising the chance that Democrats will have to hold a two night debate on September 12-13.

The latest to qualify was Julian Castro, as the former Obama Administration official now has campaign donations from more than 130,000 people, along with four qualifying polls.

Along with Castro, the other Democrats who have qualified are: Joe Biden, Elizabeth Warren, Bernie Sanders, Kamala Harris, Pete Buttigieg, Cory Booker, Beto O'Rourke, Amy Klobuchar, and Andrew Yang.

Several other Democrats have met the donor requirement, including Tulsi Gabbard, Tom Steyer, Marianne Williamson, and Jay Inslee - but they still need four polls where they have 2 percent.

The closest at this point is Steyer, who needs just one more poll; Gabbard needs two more qualifying polls.

If Steyer and/or Gabbard were to qualify by August 28, that would mean a debate field of more than ten candidates, which would then likely bring about a two night debate schedule.

Those unlikely to make the debate stage next month include Kirsten Gillibrand, Michael Bennet, Steve Bullock, Tim Ryan, John Delaney, and Bill de Blasio.

Based on polls, Inslee and Williamson also may not be included in Houston.

The first two Democratic debates featured 20 candidates, divided over two nights.