Brianna Rollins wins the 100-meter hurdles at the U.S. track and field trials to secure at spot at the Rio Olympics. (James Lang/Usa Today Sports)

While the top track and field athletes in the country battle for a spot in next month’s Summer Games, Loudoun Valley’s Drew Hunter has been watching from the stands here at Hayward Field, weighing his future well beyond these Olympics.

Just weeks before reporting for his freshman year at Oregon, Hunter instead has decided to turn pro, signing a long-term deal with Adidas.

“It was not an easy decision at all,” said the runner’s father, Marc Hunter. “Drew was very excited to go to the University of Oregon.”

Adidas, though, presented an offer that was difficult to turn down. Hunter signed a contract for 10 years that calls for Adidas to provide a tuition allowance that pays for Hunter’s college education, according to a person familiar with the deal.

“Had there not been money in the contract for school, it probably wouldn’t have happened,” the runner’s father said. “If the length wasn’t what it was, it probably wouldn’t have happened. There’s just so many things. The offer was stunning — long term, and there’s no pressure from Adidas to perform right away. They understand this is a long-term relationship.”

Hunter made headlines nationwide for his exploits as a high school runner, which included breaking Alan Webb’s high school indoor mile record and becoming the first prep runner to break eight minutes in the 3,000 meters.

Hunter signed with agent Ray Flynn and will continue to work with Tom Schwartz, his Idaho-based coach. He will train in Virginia while he and his family research their options for a permanent place for Hunter to study and run.

Rollins claims 100 hurdles

Brianna Rollins won the women’s 100-meter hurdles Friday with a time of 12.34 seconds. Kristi Castlin (12.50) was second, and Nia Ali (12.55) finished third. Queen Harrison, a Virginia Tech product, finished fourth, missing out on a spot on the Olympic team by 0.02 seconds.

Keni Harrison, who earlier this year broke the American record in the event and ran the second-fastest time ever, finished sixth.

Prandini leads 200 qualifiers

There were no surprises in the women’s 200 qualifying. Jenna Prandini posted the top time, finishing in 22.72 , followed by Tori Bowie (22.74) and Gabrielle Thomas (22.91). Allyson Felix had no problem advancing to Saturday’s semifinals, winning her heat in 22.93.

Felix, who is still recovering from an ankle injury, already has earned a spot in the 400 in Rio and is hoping to attempt the daunting 200-400 duo next month.

“I have more confidence in the ankle that it can withstand it,” she said following Friday’s heat. “Nothing has really changed between the 4 and the 2. I’m just trying to see how it does on the curve.”

Centrowitz advances

Matthew Centrowitz posted the second-best time in a rain-soaked 1,500-meter semifinal, finishing in 3:44.29, just 0.05 behind Ben Blankenship and 0.07 ahead of the third-place Robby Andrews. The three will face each other again Sunday in the final race of these trials.

“Each round is going to get more and more competitive, but our heat had a lot of previous Olympians in a pretty stacked field, so we’ve got to take each round seriously,” said Centrowitz, who took fourth in the race at the 2012 Olympics, “and honestly, I’m happy to qualify for the final. In these conditions, I don’t think anyone really wants to take the lead. It’s pretty tough to lead in the rain and win, so I kind of expected that type of race.”

In the women’s 1,500, Jenny Simpson posted the top semifinal time, finishing in 4:10.09. Kate Murphy, a rising senior at Lake Braddock, failed to advance to Sunday’s final, finishing ninth in her heat in 4:14.52.

“It was fun getting to run with the older girls. . . . I think sometimes I get too nervous,” Murphy said. “I just had a lot of nerves. But it was a really fun experience going out there, just running on Hayward Field.”

Finley wins discus

Mason Finley, a 25-year-old discus thrower from Kansas City, Mo., locked up his spot on the U.S. team with a winning throw of 208 feet 1 inch. He will be joined on the Olympic team by second-place thrower Tavis Bailey (202-0) and third-place finisher Andrew Evans (200-10). ­. . .

Evan Jager will have a chance to improve on his sixth-place finish from the London Games. He won the 3,000-meter steeplechase in impressive fashion, finishing in 8:22.48, ahead of Hillary Bor (8:24.10) and Donn Cabral (8:26.37).