The Aussie midfielder is in line to start against Melbourne Victory on Saturday.
The tournament will expand to 32 teams for the first time.
Manuel Pellegrini faces a must-win match against Southampton.
The Gunners had gone nine matches without tasting victory.
The incident occurred in a week when the league backed a 'Rainbow Laces' campaign.
The Wellington defender has undergone surgery on his shoulder.
Liverpool's lead is eight points, nearing the season's halfway point.
A 41-year-old remains in custody and is being questioned over the incident.
A fan appears to have made "racial gestures" at Manchester United's Fred.