I'm a Bball fan from Sydney, Australia and I have had the opportunity of seeing Ater Majok even before he was recruited by NCAA schools.
I still remember him when he was playing for his high school in the Under 14s team (translation team: freshman team) during an exhibition match during halftime for the new defunct: West Sydney Razorbacks.
The game was back in 2004 or so and everyone in the small 4,000 seated stadium was amazed at how tall he was for a 14 year old. Of coruse at 6'9" he dunked the game as he was playing against 14 year old kids.
My opinion of Majok as a pro player (last season he played a couple of games in the Australian league) is that he's raw offensively. Majority of the time, the points he would get are from put backs or dunks.
However, it is on the defensive end that he will contribute immensely. He will crash the boards, blocks shots and challenge anything that is put up near the rim.
I can't imagine him coming into the Lakers 15 man roster however, I think that he will go to the D-Fenders and play a season or two there and then go back overseas. In Australia, he was playing the 5 spot but that would be highly unlikely in the NBA as his frame will not allow it as he is only 6'9" 235lbs.
The highest potential is that he becomes a bench player for a number of seasons and at best an "off the bench" version of Theo Ratliff.