Park, the first Korean to win an Olympic swimming medal when he won the 400 freestyle gold in Beijing, completed an 18-month ban imposed by world governing body FINA in March after testing positive for testosterone ahead of the 2014 Asian Games.
However, under a controversial KOC regulation, he was then subject to an additional three-year ban from the national team the day the FINA suspension expired, effectively ruling him out of the Rio Olympics.
Park took his case to CAS and also filed an injunction against the KOC and Korea Swimming Federation with Seoul Eastern District Court, which ruled last week he should be considered eligible for selection again.
"We have been notified that the CAS decision will come out by 5 p.m. Korean time (0800 GMT)," the KOC said on Friday.
It added that the Seoul court's earlier ruling was intended to approve Park's status as a national team member temporarily and that the CAS ruling would supersede that.
"If CAS rules that Park does not have to be sent to the Olympic it is right to follow that decision," it added.
South Korea must submit a list of swimmers for the Rio Games to FINA on Friday. The KOC said if CAS did not hand down its decision in time it would include Park on the list pending the ruling.
CAS has previously struck down double-barrelled punishments for athletes banned for doping-related offences.
In 2011, the Swiss-based tribunal ruled that the International Olympic Committee's 'Osaka Rule', which banned athletes serving suspensions of at least six months from competing at the next Games, violated its own statutes.
Despite the KOC ban, Park entered national swimming trials in April and won all four of his races in times quick enough for Olympic qualification.
(Writing by Peter Rutherford, Reporting by Nataly Park and Lee Jeung Eun; Editing by Nick Mulvenney)
