With the lack of progress on his ailing left knee, Boston Celtics All-Star guard Kyrie Irving will get a second opinion on the injury later this week, league sources told Yahoo Sports.

Irving, 25, has missed the past three games for the Celtics to rest the knee. There was hope last week that Irving would return Sunday against New Orleans, but he remained out. Because of the lack of comfort in Irving’s knee, there is no set date for his return, league sources said.

Irving, a five-time All-Star, has averaged 24.4 points, 5.1 assists and 3.8 rebounds in 60 games this season, his first with the Celtics following a blockbuster trade from the Cleveland Cavaliers.

Boston is currently 47-23 and has a firm grip on the second seed in the Eastern Conference. The Celtics last week lost center Daniel Theis to season-ending knee surgery and guard Marcus Smart for six to eight weeks for surgery on a torn tendon in his right thumb. Celtics forward Jaylen Brown remains sidelined under the NBA’s concussion protocol.

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