Italian cyclist Giampaolo Caruso has been provisionally suspended by world governing body the UCI after a sample he gave in 2012 was retested and found to contain traces of EPO.
The 35-year-old Team Katusha rider gave the sample during an out-of-competition test in March 2012, the UCI said in a statement.
"The Union Cycliste Internationale (UCI) announces that it has notified Italian rider Giampaolo Caruso of an Adverse Analytical Finding of Erythropoietin (EPO) in a sample collected during an out-of-competition test on 27 March 2012. The sample had been stored and was reanalysed in light of new scientific developments," the statement read.
Caruso has the right to request analysis of his B sample.
Caruso is the second Katusha rider to be suspended this season after Luca Paolini tested positive for cocaine during the Tour de France.
Caruso was named in the Operacion Puerto investigation into doping in 2006 but was acquitted.
In a statement, Katusha said it was 'shocked' by news of his failed test.
"Bearing in mind the anti-doping regulations, the team will wait until the analysis of the B sample has been conducted before taking any further action or making further comment," the statement said.
"However, Team Katusha would like to underline that this news comes as a complete shock."