The tournament starting in September and lasting four 3 ½ years, will feature 15 twenty-20 games in Los Angeles, Chicago and New York.
Presently playing for Sussex in the NatWest tournament, Mahela will then participate in the Caribbean Premier League.
Thereafter, he has no other commitments in line.
The US tournament, on an idea by Sachin Tendulkar and Shane Warne, will pay 25,000 US dollars to each participating player.
Twenty eight players, including Ricky Ponting, Jacques Kallis, Adam Gilchrist, Glen McGrath and Andrew Flintoff, have confirmed their participation.