Riera's absence will hurt the Phoenix but coach Ernie Merrick welcomed the challenge.
"I think it's a good time to play a match without Albert Riera," Merrick said. "We had trouble last year; the last six games we really struggled to win a game without Albert. There was no protection for the centre backs so this is the ideal time to see if we can cover that."
Sunday's loss to Sydney FC had provided a wake-up call for the league-leaders.
"If ever we needed a kick up the backside, this was the ideal time," Merrick said.
Wellington will also be without midfielder Vince Lia (hamstring) on Sunday and Alex Rodriguez and Roly Bonevacia look the likely candidates to cover Riera and Lia.
"I don't think we'll have any problems with depth at all," Merrick said. "They'll do a job for us there."
The Phoenix will also welcome back a collection of international players, including attackers Michael McGlinchey and Nathan Burns. Reserve team member and All Whites striker Joel Stevens has suffered a shoulder injury and will be out for the season, Merrick said.
The Phoenix are on the verge of potentially winning their first Premiers Plate in the A-League.
"If we play our best football it shows what we will be capable of in the finals," Merrick said. "Now it's about results, end of story.
"There's a definite sense of confidence in the team."