A sample given in March 2012 by Italian rider Giampaolo Caruso has tested positive for EPO, the International Cycling Union (UCI) has confirmed.
The 35-year-old has been suspended by both his team and the UCI following the result.
"The team will wait until the analysis of the B sample has been conducted before taking any further action or making further comment. However, Team Katusha would like to underline that this news comes as a complete shock," the Russian team said in a statement.
Caruso, who previously served a six-month ban after testing positive for the anabolic steroid nandrolone in 2003, had been named in the Katusha team for the Vuelta a Espana, which begins on Saturday.
