Geelong has released a statement on Joel Selwood, saying they advised him not to play against GWS tonight.
Selwood suffered a concussion last week against Fremantle, and had trained all week to prove his fitness.
He flew to Sydney with the team, but Geelong ruled him out on Saturday.
They said Selwood's wellbeing is "always first priority".
Geelong has ruled out captain Joel Selwood from tonight’s match against the GWS Giants at Spotless Stadium.
“Player wellbeing is always first priority and in this case, club medical staff have advised against Joel taking to the field tonight,” Geelong’s general manager of football Steve Hocking said.
Rookie Sam Simpson will make his AFL debut tonight. The 19-year-old was elevated to the senior list on Thursday after six games at VFL level.
Simpson was selected by the club under the father-son rule in the 2016 AFL Draft.