"They were supposed to be going over to Costa Rica but we haven't had final confirmation so I don't know what is going to happen there," Merrick said.
Nations must name a preliminary 30-man squad in May, with a final 23-man squad selected by June 2.
In another blow for Wellington, defender Reece Caira's A-League season appears over after he sustained a fractured eye socket.
Caira copped a stray elbow from Adelaide's Tarek Elrich as they competed for a header.
"A fractured eye socket, with two months to go (of the season), he would be struggling to come back from it," Merrick said.
Compounding Merrick's woes is the imminent departure of a batch of his players to international duties for New Zealand - the All Whites play Japan on March 5.
"Seven, eight, maybe even nine of our boys go away and play in international matches. And I think that is a good thing, because they have got to bounce back from that (Adelaide loss), that wasn't a very good performance at all," he said.
- AAP