True, who signed a three-year entry-level contract with the Sharks on July 18, 2018, has 25 points (11 goals, 14 assists) in 40 games this season with San Jose of the American Hockey League. He was recalled Monday.
Letunov, acquired in a trade with the Arizona Coyotes on June 20, 2016, has 30 points (10 goals, 20 assists) in 39 AHL games this season. He was recalled Saturday.
The Sharks are 1-5-0 in their past six games and have been outscored 24-10 after going 5-2-1 in their previous eight games.
The Flames are 2-3-1 in their past six games following a five-game winning streak.