Vanecek, 18, was selected by Washington in the second round (No. 39) of the 2014 NHL Draft. The first European goaltender taken in that draft, he had a 2.64 goals-against average, a .921 save percentage and two shutouts in 38 games with Bili Tygri Liberec of the Czech Republic's under-20 league last season.
He represented the Czech Republic at the 2014 IIHF U-18 World Championship, where he went 4-2-0 with a 2.74 goals-against average and .897 save percentage to help win a silver medal.
He was ranked eighth among European goaltenders by NHL Central Scouting.