No kidding.

One week for St. Clair, it's Julius Peppers. Then it's John Abraham, Jared Allen and Will Smith. The list seems endless.

"That's the way it is playing left tackle in this league," St. Clair said. "I'm used to challenges."

Sunday's encounter might be the toughest one yet. Texans defensive end Mario Williams hasn't recorded as many sacks as Abraham, Allen or Peppers. He has yet to play in a Pro Bowl, though he was selected for this year's game.

But his combination of size at 6 feet 7 inches and 291 pounds with speed and strength could help him evolve into the most dominant rush end of the future.

Bears end Adewale Ogunleye even marveled about Williams' stature when the two met in Houston. And at 6-4, 260, Ogunleye is by no means small.

Williams is 10th in the league with 11 sacks and has 25 over the last two seasons. In other words, the Texans' decision to draft him No. 1 overall in 2006 over running back Reggie Bush doesn't look quite so ridiculous anymore.

"He's like a Julius Peppers," St. Clair said. "He's not as big as Julius, but his style, the way he plays and uses his long arms, is pretty much the same.

"He's an ascending player, a rare talent. The key for me against him? Just to go out and do what I always do."

Some figured St. Clair and the rest of the line would be the Bears' biggest liability. Instead the guys up front have held strong, for the most part. Yet according to STATS, St. Clair has surrendered a career-high 9.75 sacks.

"You can't go off stats because they don't know what goes on during the game," St. Clair said.

Kyle Orton certainly understands the demands put on the left tackle, the player most relied on to protect his blind side. When facing a player as talented as Williams, the onus is on the quarterback too.

"No question that you take [Williams or another end] into consideration," Orton said. "Whether it's pass protection -- and I obviously know when the left tackle is man-to-man on him and I might have to quicken up my thoughts a little bit -- or the concept, we should be able to neutralize him a little bit."

Oddly enough, sacks allowed haven't been a true indicator of how the Bears have fared. In games Orton has been sacked three or more times, the Bears are 2-2. He was sacked a season-high four times against Philadelphia in a 24-20 Bears win.

As St. Clair said, you can't always go off stats.

"The goal is not to give up any sacks," he said. "Bottom line is, I just go out and play hard every week. Whatever happens, happens. But I guarantee that I go out there and give my best effort."

vxmcclure@tribune.com