This is what I read --
On “The Dan Patrick Show,” Baffert claimed that a groom urinated in the horse’s stall after he had been taking cough medicine and Medina Spirit ate some of the hay. It is currently on the way to Baltimore, although Baffert has yet to be told if Medina Spirit will be allowed to run in this Saturday’s Preakness Stakes. A second drug test usually takes up to three weeks, so a decision may not happen right away."

-- I will try to verify via the actual Dan Patrick interview. I, and many others, stand corrected if as you say he was referring to a prior positive (even though that would still be a highly unlikely reason for any positive).

(I didn't comment about the "Cancel Culture" nonsense that he repeatedly mentioned).