Vancouver Whitecaps midfielder Matias Laba suffered a torn anterior cruciate ligament in his right knee during Saturday's loss to the New England Revolution, the club confirmed Tuesday.
The Argentine crumpled to the turf in Foxboro, Mass., in the first half before being subbed off for Andrew Jacobson in the 29th minute.
Whitecaps head coach Carl Robinson said after the match Laba's injury didn't look good, and those fears were confirmed following tests.
The 25-year designated player is expected to undergo surgery within the next two weeks and will be out until next spring.
"Mati is an important member of the club and we wish him a speedy recovery," Robinson said in a statement. "Our priority now is to support Mati and help him get back on the field as soon as possible.
"It's a big loss for us, but we have confidence in our group as we enter the final third of the season."
A fearless pit bull in the middle of the park whose main job was to protect the Whitecaps' backline, Laba joined Vancouver in a trade with Toronto FC before the 2014 season.
He started 23 games in all competitions this season, and ranks fourth all-time for the club in regular-season appearances in Major League Soccer with 113.
In terms of immediate replacements, Robinson's options include Jacobson, Canadian international Russell Teibert, and the newly acquired duo of Aly Ghazal and Aaron Maund.
The Whitecaps host the Houston Dynamo on Saturday to begin a stretch of three games in eight days.