NFL player Jeremy Kerley was suspended last month after testing positive for a performance-enhancing drug.
A month later, still confused about his test results, Kerley said he now believes a ghost "tainted his pee".
"I don't know," Kerley said when asked how a banned substance got into his system. "There's a lot of ghosts around here".
"Ghost put it in there. You know, the ghost of Christmas past? … I don't know."
At the time of his suspension, Kerley said he was "shocked" to learn he tested positive for Turinabol, an anabolic steroid, and that he never "knowingly" had taken.
"I am 5-foot-9 tall and 180 pounds, and I have never used steroids in my life. I'm a good athlete, but anyone can look at my body composition and tell that I'm not a steroid user," he said.
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"I fully intend to investigate this matter until I am able to figure out what caused the positive test, because I know that I have done nothing wrong."
Although Kerley has now served his four-game suspension he has not been put back on the active roster, keeping him on the reserve/suspended list until next week.