The club confirmed the news on Friday as McKay was ruled out of the Blues' 22-man side to face the Kangaroos on Saturday.
The matchup between McKay and his brother, Ben would have been the first game the twins went head-to-head following six years in the AFL.
— Ben Mckay (@benmckay_23) July 23, 2021
That showcase will now be on hold, as McKay is a late out for the second straight year.
Young forward Matt Owies comes into the Blues' side, with Lachie Fogarty named in the emergencies.