By CHRIS DUNCAN, AP Sports Writer

HOUSTON (AP) — Former Texans P 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, naming venue-management company SMG and the Harris County Convention and Sports Corporation as defendants. It doesn't name the Texans, but includes past comments critical of the stadium's surface by NT Shaun Cody, Patriots coach Bill Belichick and former Colts coach Tony Dungy.

"Brett has no ill will toward the Texans," said Gene Egdorf, one of Hartmann's attorneys. "If anything, Brett wishes he was with his teammates and hopes this action will help keep his teammates safe for the rest of this season and into the future."

The Texans (8-1) play Jacksonville (1-8) at Reliant Stadium on Sunday. Houston coach Gary Kubiak defended the condition of the field.

"I think our field is great. I think our guys do a great job," Kubiak said. "That's all I got to say."

The lawsuit says several doctors have told Hartmann that his knee remains "unstable" and that he needs "additional surgery, possibly quite extensive." He says he hasn't been contacted by other NFL teams since the Texans cut him in August 2012 and fears his playing career is already over.

"I'm kind of at a loss for words, not knowing what's going to happen," Hartmann said.