Ku dhameystir weedha soo socota: Kadib markii uu ciyaaray tiro kooban oo ciyaaro ah, Kostin waxaa lagu qabtay doorashadii ugu dambeysay ee wareegga koowaad ee
2017 NHL Entry Draft ee St. Louis Blues. Markii hore waxaa loo maleynayay inuu sii wado horumarinta Ruushka, Kostin waxaa laga dhigay wakiil xor ah ka dib markii Dynamo Moscow lagu qasbay inay sii daayaan dhamaan ciyaartoydooda iyada oo loo marayo jebinta xeerarka KHL 4 Luulyo 2017. Maalintii xigtay, Kostin wuxuu ogolaaday inuu qandaraas saddex sano ah la galo St. Louis Blues. Kostin wuxuu sheegay inuu doorbidayo inuu ka ciyaaro NHL xilli ciyaareedka 2017-18, in kasta oo uusan ka soo horjeedin doonin inuu aado Horyaalka Hockeyga Mareykanka (AHL), oo ah horyaalka ugu sarreeya ee horyaalka NHL; si kastaba ha noqotee ma uusan xiiseyneynin inuu ka ciyaaro WHL, ama horyaal kasta oo yar.