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One game into the season and the Houston Texans are already looking for their third different starting free safety in a month.

Tenth-year veteran Jason Simmons tore the patella tendon of his left knee in the second quarter of Sunday's 20-3 season-opening victory over the Kansas City Chiefs and will be placed on injured reserve, effectively ending his season. Houston lost its regular starter, Glenn Earl, for the entire season when he suffered a broken foot last month.

Fourth-year veteran Von Hutchins replaced Simmons on Sunday and finished with three tackles and one pass defensed. But Hutchins has played primarily at cornerback during his career and there are some concerns as to whether he can hold up physically at strong safety over the course of a full season.

Losing the versatile Simmons, who was making his first-ever start in a season opener, probably means that former Seattle starting strong safety Michael Boulware will get more playing time. The Texans dealt former first-round defensive end Jason Babin to Seattle for Boulware two weeks ago, and the fourth-year veteran has been trying to get comfortable in Houston's defense.

Boulware has started at strong safety before and is more naturally suited to the position than anyone else on the Texans' roster. He has the kind of size and aggressiveness required of the position, and Houston's coaches likely will accelerate his learning curve now to try to get him into the lineup.

"It's just bad luck," starting cornerback Dunta Robinson said. "We've had two solid guys go down at the same position, and now someone else is going to have to pick it up. But we'll get it done."

Simmons, 31, called the patella injury "a freak accident" that occurred when his foot caught in the turf. The former Arizona State star, who signed with the Texans in 2002 after spending his first four seasons in the league with Pittsburgh, will undergo surgery in the next week or so when the swelling subsides.

For his career, Simmons has appeared in 159 games, and Sunday represented just the 12th start of a tenure primarily spent as a nickel defender. Simmons has 160 tackles, two sacks and two interceptions. He had one tackle and one pass defensed in Sunday's game.

Senior writer Len Pasquarelli covers the NFL for ESPN.com.