In the 2017 Tour of the Basque Country, Sánchez was close to a stage victory, but crashed and was injured; this injury plagued him for the first half of the year. When asked if he was considering retirement, Sánchez responded that he did not know what he wanted yet, and that he would wait until after the Vuelta a España. However, a few days before the Vuelta started, an out-of-competition doping test from Sánchez came back positive for the growth hormone releasing peptide GHRP-2, and he was therefore provisionally suspended, and not allowed to start the race.