HOUSTON (AP) - Former Houston Texans punter Brett Hartmann has sued the county agency that operates Reliant Stadium, blaming ``unsafe turf'' for a possibly career-ending knee injury.

The 6-foot-2 Hartmann signed with the Texans as an undrafted free agent in July 2011. He played in the first 12 games last season before tearing his left anterior cruciate ligament and fracturing a bone in Houston's 17-10 win over Atlanta on Dec. 4.

Hartmann's attorneys filed the lawsuit Thursday in Harris County District Court. It doesn't name the Texans, but includes past comments critical of the stadium's surface by nose tackle Shaun Cody, New England Patriots coach Bill Belichick and former Indianapolis coach Tony Dungy.