After not being originally named in St Kilda's 25-man squad on Thursday night, Saad was rushed to Brisbane on Friday night as an emergency replacement for Trent Dennis-Lane.
The 23-year-old is being investigated by the AFL's anti-doping code after providing an irregular A-sample last month.
He is still eligible to play until his B-sample is received.
Veterans Nick Riewoldt and Lenny Hayes have both beaten injury and will take their place.
Rohan Bewick (Lions) and Arryn Siposs (Saints) are the substitutes.
Michael Whiting is a reporter for AFL Media. You can follow him on Twitter: @AFL_mikewhiting
