United States Track and Field is threatening to leave 2015 U.S. 800-meter champion Nick Symmonds off its world championship team if the two-time Olympian refuses to sign a contract requiring him to wear Nike-branded gear throughout all team functions, according to Ben Fischer of Sports Business Daily.

Symmonds signed on as a professional runner for Brooks Running in Jan. 2014 after a seven-year relationship with Nike. The 2013 World Championship silver medalist feels that USATF is bullying athletes that are sponsored by other companies into wearing Nike-issued gear while not in competition.

“My concern is that ... how far back can they go?” Symmonds told Sports Business Daily. “If they wanted to, they could say I have to wear Nike from the moment that I make the team at USAs, and then all of a sudden they’re buying up the entire season. USATF and Nike are just taking way too much of the pie, so far as to violate my rights as an athlete.”

Symmonds has until Sunday to sign USATF's contract or potentially faces being left off the team.

“USATF is a strong advocate for athletes to have as many sources of revenue as possible,” USATF spokeswoman Jill Geer told Sports Business Daily. “But the standard for when our team uniform and our team products must be worn is well known, and it’s consistent with the rest of the industry within track and field, internationally and also in other sports.”

USATF and Nike signed a long-term contract extension that will have the swoosh on all national team uniforms at global championships through 2040. The contract requires athletes to wear all Nike issued gear that includes apparel such as bandanas, headbands, sweatbands, etc.

Symmonds has already participated in a global championship for USATF while under contract with Brooks as he ran the 800-meter run at the 2014 IAAF World Indoor Championships in Sopot, Poland last February. Symmonds posted pictures of support to his sponsors while in Poland.

"I did not sign a statement of conditions before Poland," Symmonds told SI.com “I wore Brooks gear out there and was bullied by USATF every day.”

Symmonds' teammate Casimir Loxsom finished third in the 800-meter run at the U.S. Championship and is also sponsored by Brooks. Loxsom has already signed and agreed to his contract with USATF and will run in Beijing.

“Their contracts are the same. Nick is not the type of guy to blindly sign things when 99% of athletes do,” Brooks sports marketing director Jesse Williams told SI.com. “He is battling the USATF overreaching agreement. Really nothing to do with our athlete agreement but more based on him wanting to not be bullied into these team agreements.”

Brooks will not terminate the contracts of Symmonds or Loxsom and will continually support them in their professional and athletic endeavors.

"We support our athletes,” Williams said. “If Nick wants to fight with someone for athlete rights then we won't stop him. We obviously still would love to see him represent his country.”

Symmonds first made headlines after posting an Ebay auction for ad space on his shoulder ahead of the 2012 Summer Olympics in London. Due to IOC rules, Symmonds was forced to cover up the tattoo while in competition, which only raised more questions and attention to the bandaging. Symmonds tells SI that due to IAAF rules, he will be wearing bandages to cover up his Run Gum, a caffeinated gum product that he launched in Oct. 2014, tattoos at the world championships.

The IAAF World Championships are set to begin on Aug. 22.