EDMONTON, Alberta -- Mattias Ekholm will not be available for the Edmonton Oilers' first-round playoff series against the Los Angeles Kings, coach Kris Knoblauch said Monday.

Ekholm's absence is a significant blow to the defending Western Conference champions' blue line in their attempt to make another long playoff run this spring.

The talented and rugged top-pairing defenseman returned to action Friday in Edmonton's 4-2 win over visiting San Jose after a seven-game absence because of an undisclosed injury. But he left the game when he aggravated the ailment after playing a couple of shifts.

Ekholm, a 34-year-old Swede, has nine goals and 24 assists in 65 games this season. He also played for Sweden in the Four Nations Face-Off this year.

The Oilers are facing the Kings in the playoffs for a fourth consecutive year. They expect to get MVP candidate Leon Draisaitl back for the series after he has been dealing with a nagging injury, while reigning playoff MVP Connor McDavid is resting late in the regular season after also missing time.

The Associated Press contributed to this report.