Lettieri was called up from AHL Toronto on Sunday, per David Alter of The Hockey News.
Per Alter, Lettieri was expected to rejoin the Marlies on Sunday, but he'll ultimately stick with the Maple Leafs. While it's unclear whether the 31-year-old was officially sent down to the AHL, the decision to keep him in the NHL was likely impacted by Artur Akhtyamov's return to the AHL. When active for the Maple Leafs this season, Lettieri has posted a goal, eight shots on net, 24 hits and nine blocked shots across eight outings.