ESPN's Adam Schefter reports that Houston Texans linebacker Brian Cushing tested positive for "slightly elevated levels" of HCG, a non-steroidal substance produced naturally by the body.

"It is in seminal fluid and slightly elevated levels can be discovered in the event that a test occurs soon after ejaculation", Schefter added on Twitter.

hCG is on the list of banned substances because in addition to being used as a female fertility drug, hCG is typically used by steroid users to restart their bodies' natural testosterone production as they come off a steroid cycle.

Use of hCG earned Los Angeles Dodgers outfielder Manny Ramirez a 50-game suspension in 2009.