Castagna was promoted from AHL Calgary on Wednesday.
The Flames had just 12 healthy forwards on their roster, so they summoned Castagna and Aydar Suniev to give them some extra options ahead of Thursday's game against the Avalanche. The 21-year-old Castagna is off to a strong start with two goals in two AHL outings this year. He had 15 goals and 34 points in 34 appearances with Cornell University in 2025-26.