Muhammed "King Mo" Lawal had expressed hopes of winning a Strikeforce title again following his win over Lorenz Larkin at Strikeforce: Lukehold vs. Jardine.
Now the former light heavyweight champ could be out for a year thanks to controversy.
Drostanolone is often used for bodybuilding and cutting cycles.
In his recent match up Larkin, Lawal dominated his opponent with overpowering wrestling and ground and pound.
Sport's illustrated Lorreta Hunt, she's seen "Drostanlone connected to injury recovery most in the explanations given by fighters that have tested positive for it in the past."
Hunt also tweeted that Lawal told her he didn't take any steroid before the fight.
Lawal is the second Strikeforce fighter who has failed a drug test this month.
Strikeforce women's featherweight champion Cristiane "Cyborg" Santos was suspended earlier in the month for testing positive for anabolic steroids.
If Lawal is punished like other first time offenders in MMA, he could face up to a year suspension and get fined.
This is bad news for Strikeforce which is already short handed on fighters.
The company recently dissolved it's heavyweight division to the UFC.
Strikeforce also lost champions Dan Henderson, Nick Diaz, and Alistair Overeem to the UFC last year.
Now they will be without arguably one of it's most promising and entertaining stars.
Stay tuned to Bleacherreport MMA for the latest updates.