The Mavericks fear that starting center Dwight Powell suffered a season-ending torn right Achilles tendon early in the first quarter of Tuesday night’s 110-107 loss to the LA Clippers. “It’s a somber night with Dwight’s situation,” Dallas coach Rick Carlisle said. “He’s going to have an MRI tomorrow. Right Achilles injury feared to be severe, but we won’t know for sure until the diagnostic tests are done. It’s a real tough one.”