Pittsburgh Penguins defencemen Kris Letang has been retroactively placed on injured reserve dating back to Dec. 24, the team announced Thursday.

Defencemen Chad Ruhwedel and forward Bryan Rust have also been placed on IR.

Details regarding the gravity of the injuries to the players have not been disclosed.

Subsquently, the Penguins have recalled goalie Casey DeSmith, defenceman Andrey Pedan and forward Garrett Wilson from the Wilkes-Barre/Scranton Penguins of the American Hockey League.

Letang, who was drafted 62nd overall by the Penguins in 2005, has recorded two goals and 23 assists in 37 games this season. He has helped the Penguins win three Stanley Cups (2009, 2016 and 2017)

Ruhwedel has a goal and two assists in 30 games this season; while recorded 18 points (4G, 14A) in 38 appearances.