Francis Tiafoe literally grew up around tennis, often spending nights at a Maryland tennis center where his father worked. At only 16, he is ranked number two in the world. Could a future U.S. champion be in the making? (Lee Powell/The Washington Post)

Three of Wimbledon’s top 10 men’s seeds will compete in next month’s Citi Open, the annual hard-court classic at Rock Creek Park’s William H.G. FitzGerald Tennis Center.

Headlining the field is top American John Isner, who will be joined by the equally big-serving Milos Raonic of Canada and Japan’s rising star, Kei Nishikori. They are seeded ninth, eighth and 10th, respectively, at Wimbledon, which gets underway Monday.

Formerly known as the Legg Mason Classic, the event also includes a women’s tournament that’s one rung below the elite tour. This year it features 13th-ranked Eugenie Bouchard, who reached the semifinals of the recent Australian and French opens; 18th-ranked Sloane Stephens, the No. 2 American; rising American star Madison Keys, who claimed her first WTA title Saturday at Eastbourne; and 2010 French and 2004 U.S. Open champion Svetlana Kuznetsova.

The world No. 1 doubles team of Bob and Mike Bryan has committed to a doubles field that will be announced later.

With a $1.5 million purse, the Citi Open is one of 11 ATP 500-level events, placing it among the 20 most prestigious tournaments based on prize money and caliber of the field. Coming three weeks before the U.S. Open, it’s a key tuneup for the season’s final Grand Slam.

In addition to Isner, other American hopefuls include Sam Querrey, Jack Sock and Donald Young — all among the top 100. Riverdale Park’s Francis Tiafoe will try to earn a spot in the 48-player main draw, having won the tournament’s wild-card challenge in College Park earlier this month.

Other top 25 players in the men’s draw: fan favorite Gael Monfils of France; Bulgaria’s gifted Grigor Dimitrov, who has won three ATP titles this season; and Richard Gasquet, the top-ranked Frenchman.

The 32-player women’s tournament, part of the WTA International Series, has a purse of $220,000.