Whakakiia te rerenga e whai ake nei: Na te takaro i te maha o nga keemu, i tangohia a Kostin me te kowhiringa whakamutunga i te rauna tuatahi o te
2017 NHL Entry Draft e te St. Louis Blues. I te tuatahi i whakaarohia kia haere tonu ki te whakawhanake i Russia, i hangaia a Kostin hei kaihoko koreutu i muri i te tohe a Dynamo Moscow ki te tuku i a raatau kaitakaro katoa na te takahi i nga ture KHL i te 4 o Hurae 2017. I te ra i muri mai, i whakaae a Kostin ki te kirimana taumata whakauru mo te toru tau me te St. Louis Blues. I kii a Kostin ka pai ia ki te purei i te NHL mo te waa 2017-18, ahakoa kaore ia e whakahe ki te haere ki te American Hockey League (AHL), te hononga riiki iti mo te NHL; heoi kaore ia i hiahia ki te purei i te WHL, i tetahi riiki rangatahi ranei.