Kevin Durant could sign a deal worth as much as $30 million per year with Under Armour.
Durant's seven-year, $60 million deal with Nike is expiring.
Under Armour is based in Durant's home state of Maryland.
Nike and Adidas are also in talks with Durant.
A deal with Under Armour could also be beneficial to the Washington Wizards, one of several teams that are expected to pursue Durant when he hits free agency in 2016. Ted Leonsis and Under Armour Founder/CEO Kevin Plank, a University of Maryland graduate, have been involved in several philanthropic endeavors in the D.C. area.