Portland Trail Blazers star Damian Lillard underwent a cortisone injection procedure to his abdominal last week to mitigate the pain he’s been dealing with for the last few years, league sources told Yahoo Sports. Lillard, 31, is scheduled to be reevaluated on Friday and could return to action as soon as Sunday against the Minnesota Timberwolves, sources said. The pain had reached a heightened point before the procedure.