Mantha will undergo season-ending ACL surgery on his knee Thursday.

Mantha (lower body) was designated for injured reserve Thursday, Wes Gilbertson of the Calgary Sun reports.

Mantha (lower body) wasn't at practice and will miss Thursday's game in Boston, Pat Steinberg of Sportsnet 960 The Fan reports.

Calgary head coach Ryan Huska wants Mantha to shoot more, Wes Gilbertson of the Calgary Sun reports. "You saw tonight, there was multiple times he was standing right in front of the net," Huska praised. "That's how he scored his goal. And for a guy that is his size and has his ability with the puck, that's what we need out of him."

Mantha posted an assist and three shots on goal in Saturday's 6-3 win over the Flyers.

Mantha signed a one-year, $3.5 million contract with Calgary on Monday, Renaud Lavoie of TVA Sports reports.

Mantha (undisclosed) practiced without an injury designation Sunday, Danny Webster of the Las Vegas Review-Journal reports.

Mantha (undisclosed) is expected to remain on the shelf against the Ducks on Thursday, Danny Webster of the Las Vegas Review-Journal reports.

Mantha (undisclosed) practiced Wednesday but didn't take contact, Danny Webster of the Las Vegas Review-Journal reports.

Mantha will miss Tuesday's matchup with Chicago due to an undisclosed injury, Jesse Granger of The Athletic reports.