Sri Lanka's wicketkeeper-batsman Kusal Perera faces a four-year ban after his B sample also tested positive for a prohibited substance.
The 25-year-old failed an out-of-competition anti-doping test in October.
He was sent home from his side's tour of New Zealand earlier this month.
"We are appealing against this and will back him with legal representation," said Sri Lanka sports minister Dayasiri Jayasekara.
|Kusal Perera's international statistics|
Jayasekara had earlier claimed the failed test could be part of a "conspiracy" against Perera to keep him out of next year's T20 World Cup.