Supercross rider James Stewart suspended for 2015

James Stewart, the supercross champion who has wowed fans with his feats, has been suspended for the 2015 season.

Stewart, a two-time AMA Supercross champion, and his team Yoshimura Suzuki will appeal, according to a story in the Los Angeles Times.

Stewart failed a drug test administered April 12 and was suspended by the Federation Internationale de Motocyclisme June 20.

At that time, the rider told his team he learned of the failed test June 17 and said the positive result of amphetamines was triggered by a medicine prescribed by his physician to help treat a long-term condition.

"We plan to appeal as I personally feel the punishment far outweighs the situation," Stewart said in a statement Wednesday, according to the Times. "I'm extremely disappointed to say the least."

Stewart's team said the amphetamines came from Stewart's prescribed use of Adderall to treat an unspecified "long-term condition," according to the Times. Adderall can be used to treat attention deficit hyperactivity disorder.

The 16-month suspension is retroactive to the original failed test, and will run through Aug. 11, according to the Times.

Stewart, who became the first African-American to win a major auto-racing title when he won the first of two AMA Supercross crowns in 2007, won again in 2009. He won world titles in 2006 and 2007.

The Supercross season opens Jan. 3 at Angel Stadium and runs through May 2. Stewart finished fourth in the series in 2014.