ANAHEIM, Calif. -- Anaheim Ducks rookie forward Leo Carlsson will be out for four to six weeks with a sprained right knee ligament.

The Ducks announced the extent of the injury for the No. 2 overall pick in last summer's draft before they hosted the Seattle Kraken on Saturday night in their final game before the holiday break.

Carlsson, who turns 19 on Tuesday, was hurt during Anaheim's home loss to the Calgary Flames on Thursday. Although the injury looked potentially severe, the Swedish playmaker apparently won't need surgery on any torn ligaments in his knee.

Carlsson couldn't put any weight on his right leg after Flames defenseman MacKenzie Weegar fell on Carlsson's side.

"Weegar there was lunging, and then Leo lost his balance," Anaheim coach Greg Cronin said after the game. "You could see when Weegar fell on him, any sport when that happens, it's not good."

Carlsson is off to a solid start in his first NHL season with eight goals and seven assists in 23 games while playing as the Ducks' first-line center.

Anaheim defenseman Radko Gudas also was ruled out of the club's game against Seattle with a lower-body injury. He will be re-evaluated after the NHL's holiday break.

Star forward Trevor Zegras is returning to face the Kraken after a 20-game absence with a lower-body injury. He is likely to take Carlsson's spot on Anaheim's top line.

The No. 9 overall pick in the 2019 draft, Zegras, 22, has a goal and an assist in 12 games this season after posting a career-high 65 points, including 23 goals, last season in 81 games.

The Associated Press contributed to this report.