Athletic Bilbao defender Yeray Alvarez has been provisionally suspended after testing positive for a banned substance during a UEFA Europa League match against Manchester United in May.
The 30-year-old centre-back revealed on Thursday that the substance was taken “involuntarily” through medication used to treat hair loss—a side effect of his previous battle with testicular cancer.
Alvarez, who was first diagnosed in 2016 and made two comebacks following a relapse in 2017, said the prohibited substance was found in a treatment he has used for years to combat alopecia.
“After overcoming my illness, I have been taking a treatment against alopecia for years, and after studying the issue, we have found out that the positive test came because I involuntarily took a preventative medicine against hair loss which contained a prohibited substance,” Alvarez said in a statement.
He added that the disciplinary process is currently in an investigatory phase and, as such, is confidential. He is provisionally suspended and not authorised to comment further.
The positive test followed Athletic Bilbao’s 3-0 home defeat to Manchester United in the Europa League semi-final first leg on May 1. Alvarez featured in the return leg and in two additional La Liga matches before being informed of the test result weeks later—a revelation he described as “a very tough blow.”
“I could not believe it, given that never in my life have I taken prohibited substances,” he said.
Athletic Bilbao issued a statement expressing support for Alvarez, describing the situation as a “human error” and affirming their continued backing of the player. However, the club said it would not provide further comment due to the ongoing investigation.
UEFA has not yet responded to requests for comment on the matter.