Three of them are the fumbles he had during the Pittsburgh Steelers' final two exhibition games - the fumbles that prompted his teammates to make him carry a ball everywhere he went the following week.

"It is not a secret," Ravens linebacker Ray Lewis said Wednesday. "He has fumbled the ball a couple of times, so that would be our focus. I think we would be approaching the game wrong if that were not our focus."

That Ravens defense can offer up 21 more reasons for the Steelers' first-round draft pick to be apprehensive about filling in for Pro Bowl running back Willie Parker, who has a sprained knee. The Ravens (2-0) haven't allowed a 100-yard rusher in 21 games, the NFL's longest current streak.

Also, the Steelers managed only 136 yards rushing in two games against Baltimore last season. The Ravens have allowed the fewest yards of any NFL defense this season, though their opponents were winless Cleveland and Cincinnati.

"That's a daunting task, getting your first opportunity for significant playing time versus that defense," Steelers coach Mike Tomlin said. "Everybody knows what they're capable of."

Then there's the Steelers' blocking problems, which showed up repeatedly during their 15-6 loss Sunday at Philadelphia. Not only did the Steelers (2-1) allow nine sacks, they ran for 33 yards on 19 carries, an abnormally low total for a team that runs the ball as consistently as Pittsburgh does.

So why does Mendenhall look so relaxed to his teammates, walking around the Steelers' practice complex this week as if he's readying for another game at Illinois?

"It's just regular nerves like I have for any game," said Mendenhall, whose only 10 NFL carries came during a one-sided win against Houston on Sept. 7. "You prepare for every game the same. I'll just be out there a little more. It's more excitement."

Another reason, he said, is he has been practicing since May and feels comfortable in the offense. He ran for 158 yards in the final two preseason games, but that production was overshadowed by his fumbling.

"I had a lot of experience in the preseason and early in the season, so I'm just looking forward to going in there," Mendenhall said. "You have to make sure you have your assignments down and have an idea what they're going to do so, come gametime, you've seen it all before."

Right tackle Willie Colon thinks he knows why Mendenhall appears so calm. To Colon, any back with the talent Mendenhall possesses would naturally be confident, regardless of his lack of experience.

"Just how he carries himself around here, I'm pretty sure he's going to be able to handle the pressure," Colon said. "I think he'll do fine. I think he's a mature kid. He's an intense kid. It's going to be his first intense game. It's the big time, a big stage, but that's why he's our first-rounder."

The Steelers' inability to run the ball when Parker got hurt last season - they had only 92 yards on 38 carries in two games after he broke his right leg Dec. 20 - was a major reason they used their first-round draft pick on him. Running back already was a position of strength for the Steelers, with Parker coming off three successive 1,000-yard seasons, yet they wanted to make it stronger.

"He's not Willie Parker and he doesn't need to go out and try to be Willie Parker," quarterback Ben Roethlisberger said of Mendenhall. "He needs to go out and be the best Rashard he can be and we've got confidence he can get it done."