Kanstantsin Siutsou has returned an Adverse Analytical Finding (AAF) for blood booster EPO, the UCI announced on Wednesday.
The Belarusian rider for Bahrain-Merida returned the positive in an out-of-competition test on July 31, in a planned control by the Cycling Anti-Doping Foundation (CADF).
Siutsou is now provisionally suspended and has the right to request and attend the testing of his B sample.
The 36-year-old, who won the overall at the Tour of Croatia this year, began his professional career back in 2001 and has ridden for a number of top teams in that time.
His best result, a stage win at the Giro d'Italia in 2009, came in a four year stint with Team Columbia/HTC-Highroad, with whom he also took ninth overall in the Giro in 2011.
Siutsou then moved to Sky in 2012, where he rode in two Tour de France winning teams, although abandoned the 2012 edition won by Bradley Wiggins on stage three.
He then moved to Dimension Data in 2016, before signing for two years with Bahrain-Merida in 2017. Siutsou is a four-time Belarus national time trial champion, and last rode at the Clásica San Sebastián in August which he abandoned before the finish.
His current team said in a statement that the finding was "terribly disappointing" and added that they had already notified him that his contract would not be renewed when it expires in December.
"It is with deep disappointment that we have been informed by the Union Cycliste International (UCI) that our rider Kanstantsin Siutsou, has been notified of an Adverse Analytical Finding (AAF) in a sample collected in the scope of an out-of-competition control on 31st July 2018," the team said.
"In accordance with our zero tolerance policy, the rider has been suspended immediately.
"Siutsou’s contract expires on December 31st 2018 and Bahrain-Merida Pro Cycling Team had notified the rider during the month of June that his contract would not be renewed."
Brent Copeland general manager of the team said: “This news is terribly disappointing, we are very severe with any wrong doing with regards to our internal health code, this behaviour is not accepted by our team and further procedures will be taken against the rider.”
