Olympic hopeful Shelby Houlihan has been banned from competitive running for four years after testing positive for nandrolone, an anabolic steroid.

Houlihan’s suspension means the 28-year-old American record holder in the 1,500 and 5,000 meters will miss this month’s U.S. Olympic track and field trials.  In a post published to her Instagram account, Houlihan explained that a pork burrito she consumed could likely be to blame for what she sees as a false positive. The World Anti-Doping Agency has warned about trace amounts of nandrolone in pig offal triggering a positive test for the steroid.

Houlihan said she was first notified of her positive test by the Athletics Integrity Unit back in January. Her four-year suspension from the sport was then upheld on June 11 after the Court of Arbitration denied her false-positive explanation. Houlihan’s ban means she will miss both the 2021 Olympics and the 2022 world championships.