FC Dallas defender Matt Hedges faces an extended spell on the sidelines after suffering a torn meniscus in his left knee.
A club spokesperson confirmed Hedges' injury to MLSsoccer.com on Monday.
Hedges last played last Wednesday in a 3-1 win over Portland but was not in the squad that defeated Sporting Kansas City on Sunday.
The 26-year-old, who was among last season's finalists for MLS Defender of the Year, could miss four to six week, Goal.com reported.
Zach Loyd started at center-back in Hedges' place on Sunday alongside Walker Zimmerman as FC Dallas won 2-1.