Jon McKain and Ben Sigmund are vying for the centre back spot alongside Wellington Phoenix captain Andrew Durante for Saturday night's A-League preliminary final against Sydney.
McKain was unavailable because of suspension for the extra-time win against the Newcastle Jets last weekend and Sigmund will return from New Zealand international duty to play the full 120 minutes at Westpac Stadium.
Coach Ricki Herbert said a decision was unlikely to be reached until after Friday afternoon's training session in Sydney.
But McKain would appear to be the front-runner after forming a strong partnership with Durante in recent weeks.
McKain said he would approach this week like any other whether he's picked or not.
"Both Siggy and I have done well when we've come in. It's a tough decision only Ricki can make," he said.
"It's a must-win game. Ricki will do what he thinks is best and what's best for the team."
"Whatever happens, if Siggy plays I'll be there supporting him and if I play I'm sure he will be the same. So be it. The important thing is getting a result and hopefully we can do it on Saturday night," McKain said.
Standing between the Phoenix and a grand final date with Melbourne, Sydney has beaten the Phoenix three times already this season.
But McKain was adamant that counted for little with so much at stake in Saturday's showdown.
"We've had a bad score with them losing three times but finals time anything can happen. It's a one-off game."
"We're going in confidently. Hopefully they will be a bit down after their loss (to Melbourne) and we can produce a surprise," McKain said.
Alex Brosque has been a key figure for the Sky Blues in all three victories, which has seen Sydney rack up six goals and concede only one.
McKain acknowledged the Phoenix defence could not afford to switch off against one of the best strikers in the league.
"He's got a blistering turn of speed that can hurt anyone," McKain admitted.
"We've got to be on our guard. He's one that drifts in and out. He likes to get in the middle and drift wide and it's hard to man-mark him."
"We're aware of what he's going to bring to the table and hopefully we can deal with him better than we have in previous times because we haven't been as successful as we would have liked."
Since the early-season losses, the Phoenix has tinkered with its formation and brought Manny Muscat into a defensive midfield role behind workhorses Vince Lia and Tim Brown.
Troy Hearfield was also switched to right back.
It's been a successful ploy with the Wellington club winning eight of its last 10 games, including the last five in a row, to take them to within touching distance of the league's showpiece finale.
"A lot of teams are talking about us not being the flashest team in the competition but we've got great balance and I think any team needs balance," McKain said.
"That's something we've got in this team in abundance – balance and a bit of depth."
"We've had a good run (to the preliminary final) and no-one really gave us a chance. Now they are starting to talk about us and hopefully we can keep our form going and hopefully produce another surprise on Saturday night."