Mavericks guard Luka Doncic faces another spell on the sidelines after reinjuring his problematic right ankle Thursday.The newly selected All-Star suffered another sprain in practice and will miss Friday’s game against the Rockets. Dallas expects to have a clearer picture of the problem once Doncic, 20, undergoes an MRI.DEBATE: Who will own the next decade in sports: Luka or Lamar? “Luka turned his right ankle in practice,” Mavs coach Rick Carlisle said in quotes published on the team’s website. “He’s getting treatment right now. We don’t know the status. We obviously hope it’s not serious. But we don’t know.”Doncic missed four games after spraining the same ankle during an overtime loss to the Miami Heat in December. Whether the reigning NBA Rookie of the Year will be fit to start his first All-Star Game on Feb. 16 remains unclear. Veteran guard J.J. Barea said: “Stuff happens. Playing hard basketball and stepped on somebody. We hate it that it happened at the end of practice to Luka, but he’s a tough kid. We’ll see what happens, but hopefully it won’t be that long.”In his second NBA season, MVP candidate Doncic is averaging 28.8 points, 9.5 rebounds and 8.7 assists.The Mavs could also be without Tim Hardaway Jr. against the Rockets after listing him as questionable due to tightness in the lower back region.