UPDATE 2-Athletics-Houlihan's future at U.S. trials in doubt amid controversy

(Adds USOPC statement)

EUGENE, Oregon, June 18 (Reuters) - American record-holder in the 1500m and 5000m Shelby Houlihan appeared unlikely to run in the U.S. Olympic Track and Field Trials on Friday, after a lengthy back-and-forth over her eligibility that rocked the Tokyo qualifying events before they had even begun.

Houlihan was included in the starting line-up for those two events in Eugene, Oregon, despite receiving a four-year ban for testing positive for an anabolic steroid.

Without addressing Houlihan directly, USA Track & Field (USATF) earlier said that any athlete facing an active appeal process would be allowed to compete at the trials, which kick off on Friday.

The Athletics Integrity Unit (AIU) swiftly responded, saying on Thursday it has written to USATF to stress that middle distance runner Shelby Houlihan was prohibited from competing in this month’s Olympic trials.

The AIU said it had written the USATF and that the 28-year-old’s participation was “strictly prohibited.”

USOPC CEO Sarah Hirshland appeared to close the chapter on the matter in a statement issued Thursday: “The U.S. Olympic & Paralympic Committee, together with USATF, can confirm that we will adhere to the WADA Code and any CAS decisions that govern athlete participation in sanctioned events.”

Neither Houlihan nor her lawyer were immediately reachable for comment.

Houlihan said this week the AIU informed her in January that a test showed she had returned an “adverse analytical finding” for nandrolone. She denied knowingly ingesting the substance and said she was innocent of any wrongdoing, saying in an announcement posted on social media that a pork burrito she ate the night prior to the test was likely to blame.

A group of athletes, including 2016 3,000 meter steeplechase bronze medalist Emma Coburn, 2018 Boston Marathon winner Des Linden and marathon runner Molly Seidel, penned an open letter here voicing their objection to Houlihan's participation.

“It creates an opportunity for athletes convicted of doping to compete in the future, which is not a standard that’s ever been applied in the past,” the athletes said in a letter issued via the Clean Sport Collective. (Reporting by Gene Cherry; Writing by Amy Tennery; Editing by Jane Wardell and Christopher Cushing)