Siutsou moved to Team High Road for 2008, where he took his first stage race overall victory at the Tour de Georgia, and came 16th overall in the Tour de France. In the 2009 Giro d'Italia, Sivtsov won his first two Grand Tour stages, the team time trial on stage one and a successful solo breakaway in stage eight.
In October 2015, he announced that he would be leaving Team Sky after four seasons to join Team Dimension Data for 2016.[6]
Doping case
On 5 September 2018, the UCI announced that an out of competition test had resulted in an adverse analytical finding of Erythropoietin in a sample collected 31 July 2018. Siutsou was provisionally suspended pending the result of any B sample test.[7] This followed his back injury sustained whilst carrying out a recon of the time trial at the Giro earlier that year.[8]
On 23 June 2020, he was given a four-year ban for doping using EPO.[9]