Dallas Mavericks star Luka Dončić exited Wednesday’s 105-99 loss to the Minnesota Timberwolves with a left calf injury, raising concerns about his availability moving forward. According to ESPN’s Shams Charania and Tim MacMahon, the Mavericks are “bracing” for Dončić to miss an extended period of time. The incident occurred in the second quarter of the Christmas Day matchup at the American Airlines Center. Dončić, while making a move at the elbow, suddenly pulled up and passed the ball away. He immediately started limping and appeared visibly distressed as play continued. Dončić eventually walked off the court under his own power…