Wales fly to New Zealand on Monday still unclear when France-based lock Luke Charteris will join the party.
Racing 92's Charteris and Clermont Auvergne centre Jonathan Davies both missed the 27-13 defeat by England because they were on club duty.
Both have to be released eight days before the first Test against the All Blacks in Auckland on 11 June.
Asked when he expected Racing to release Charteris to join the squad, Gatland replied: "I don't know."
And he added: "He's got to be in New Zealand ready to train on the Monday before the All Blacks game [6 June] under World Rugby regulations.
"So it's just when Racing release him to fly out."
Gatland was already resigned to Davies arriving late, though Charteris was originally expected to fly out with the main party.
Fourth-placed Racing are battling for a home draw in the French domestic league play-offs.
They play second-placed Montpellier on Sunday, 5 June in the final game of the regular season - six days before Wales play world champions New Zealand.
If Charteris were to play against Montpellier, he would not arrive in time for training on 6 June.
Kiwi changes hint at strength
Gatland hinted that he needs as many of his front-line players as possible available to face the All Blacks who will be playing their first matches since beating Australia 34-17 in the World Cup final.
Wales have not beaten New Zealand in 22 attempts since 1953 and have never beaten them in New Zealand.
World Cup captain Richie McCaw, as well as Keven Mealamu and Tony Woodcock have retired - while Dan Carter, Conrad Smith and Ma'a Nonu have all joined clubs in France.
|Wales' summer fixtures:|
|11 June: New Zealand (Auckland)|
|14 June: Chiefs (Hamilton)|
|18 June: New Zealand (Wellington)|
|25 June: New Zealand (Dunedin)|
So former Wales coach Steve Hansen has named six uncapped players in his squad for the three-test series.
"Reasonably predictably they've brought some new faces in," said Gatland.
"I think the two Highlanders loose forwards that have come in Elliot Dixon and Liam Squire have obviously had outstanding seasons.
"There are definitely some excellent players but when you look through the number of caps and that there's a fair bit of inexperience in some of those positions as well.
"If you take away Brodie Retallick and Sam Whitelock in the second row the others are reasonably inexperienced and there's not a huge amount of experience in the midfield too.
"But you don't underestimate the All Blacks because they will be a quality side."