On Tuesday, former housing secretary Julián Castro became the 10th Democratic presidential candidate to qualify for the September Democratic debates. Castro qualified with a CNN poll, which had him above 2%, becoming the fourth poll to do so.

Candidates were required to have a minimum of 130,000 unique donors and register at 2% in at least four qualifying polls.

In reaching the qualifications, Castro joins former Vice President Joe Biden, Sens. Cory Booker, Kamala Harris, Bernie Sanders, Amy Klobuchar and Elizabeth Warren, Mayor Pete Buttigieg, former Representative Beto O’Rourke and entrepreneur Andrew Yang.

“With two standout debate performances, Secretary Castro has been building momentum for his candidacy,” his campaign manager, Maya Rupert, said in a statement reported by the New York Times. “He has never wanted to be a ‘flash in the pan’ candidate, but rather has continued to build support and momentum by leading the field on critical issues and showing voters every day why he’s the best candidate to go toe-to-toe with Donald Trump.”

Castro has made concerted efforts to raise his profile, recently posting an ad he purchased during Fox News calling out President Trump for his racist language, which many connected to the manifesto written by the shooter in El Paso, Texas.

The September debate is scheduled for Sept. 12-13 at Texas Southern University and would need only one more candidate to allow for the second debate night to become necessary. If no other candidates reach the qualifications before August 28, the debate will be a one-night-only affair.

Currently, the candidate closest to qualifying is Tom Steyer, a billionaire who has announced that he has surpassed the donor qualification but needs one more poll in order to reach the threshold. Hawaii Rep. Tulsi Gabbard has also reached the donor threshold but needs two more polls to qualify and has suspended her campaign in order to fulfill her obligations to the National Guard, according to the New York Times.