North suffered the injury in Saturday's 39-21 defeat to the All Blacks in the first test at Eden Park.
"They're not too sure yet if it's a significant tear," Gatland said in comments published by Fairfax Media on Monday. "They're not sure if he needs an operation or not.
"It's unfortunate because it's a big loss for us. Hopefully he gets a good break in the off-season and comes back."
The 24-year-old had been one of the standouts in the first test for Wales, who have drafted in Rhys Patchell of the Cardiff Blues and Ospreys' wing Keelan Giles as injury cover.
Patchell, 23, has two caps from the 2013 tour to Japan while Giles is uncapped. The 18-year-old was pulled out of the Wales party competing in the under-20 world championship in Manchester.
Gatland will welcome the new arrivals given they have a tough week ahead having to play Super Rugby side the Waikato Chiefs on Tuesday before the second test in Wellington on Saturday.
Gatland played 140 games for the provincial Waikato side and said the match against the two-time Super Rugby champions was an opportunity for players to press for test spots.
"It was important we had a big enough squad for the three tests but also to provide game time for the players on tour and this match gives the players a chance to stake their claim for the final two tests against the All Blacks," he said.
"The Chiefs are without a number of their All Blacks but still boast a strong side, and from my playing days I know they will be right up for the fixture against a touring nation."
Lock Luke Charteris will lead a vastly revamped Wales side in Hamilton, with none of the starting test team named, though all eight substitutes from the Auckland game will play, with former Chiefs player Gareth Anscombe named as a replacement.
"It will be a good occasion for the Chiefs," All Blacks flanker Sam Cane, a co-captain of the Super Rugby team, told reporters.
"I'm pretty sure the Chiefs will play as they do and it will be tough for some of those Welsh boys to back up."
(Reporting by Greg Stutchbury, additional reporting by Toby Davis; Editing by Peter Rutherford)
Share
