PITTSBURGH -- The running back was confused about his assignments and didn't appear to know his playbook, so he found himself on the bench. No carries, no yardage, no recognition.

Happens all the time in Pop Warner football, and high school ball, too. College football? Not so often. The NFL? C'mon, you've got to be kidding.

Rashard Mendenhall is the embarrassed exception.

One week after tearing off a 39-yard run against Chicago that demonstrated some of the ability that caused the Pittsburgh Steelers to make him a first-round draft pick last year, he didn't carry once against Cincinnati.

You learn in the NFL that the minor things are major, so you have to stay on top of everything. I just look forward to getting an opportunity to get to play and show the fans and my teammates what I can do.

-- Rashard Mendenhall

Coach Mike Tomlin denied him the ball, effectively saying that if Mendenhall played like he practiced, he didn't want to see what might happen in a game that counted.

Now, with Pittsburgh (1-2) facing a pivotal game Sunday against the San Diego Chargers (2-1), the Steelers want to see if Mendenhall is getting the message before they give him the ball. Even if Willie Parker's big toe injury might leave them with no other option other than Mendenhall and third-down back Mewelde Moore.

"We're here now, that's in the past, it's another week," Mendenhall said.

What Mendenhall must be concerned about is whether the Steelers are willing to put his bad week into the past so quickly, since he has repeatedly disappointed them.

A year ago this week, he irritated them by bragging to a friend with Baltimore that he expected a big game against the Ravens. Baltimore's defense was motivated by the comments, and linebacker Ray Lewis put him out for the season with a fractured shoulder.

The Steelers didn't see much of Mendenhall after that as he only occasionally stopped by their practice complex during his rehabilitation. He said he spent some time going to museums and doing the things football players don't normally do during the season. Especially Steelers players, injured or not.

It didn't help when he had an ineffective training camp this summer, again failing to flash the strong cutting ability, durability and power he displayed in college at Illinois.

"It's a learning experience," Mendenhall said. "You learn in the NFL that the minor things are major, so you have to stay on top of everything. I just look forward to getting an opportunity to get to play and show the fans and my teammates what I can do."

The Steelers are waiting to see it, too. Parker, a three-time 1,200-yard runner, is unsigned past this season and the job was expected to go to Mendenhall if Parker didn't return.

Tomlin said that if a player such as Hines Ward is momentarily confused and doesn't run the correct pass route, a coach simply moves on. But that coach can't be as forgiving if a young player such as Mendenhall or wide receiver Limas Sweed makes such a mistake.

A week after Mendenhall was stuck to the bench except on special teams plays, Sweed may find himself there this week. Sweed dropped a pass in the end zone Sunday during the 23-20 loss in Cincinnati, much like he dropped what would have been a key reception during the AFC championship game against Baltimore in January.

Fool me once, shame on you; fool me twice, shame on me. Twice was enough for Tomlin, who hinted Sweed won't see the ball again until the Steelers are convinced he won't drop it.

Mendenhall's change for redemption may arrive a little sooner.

"Young guys ... have to make coaches comfortable with their ability to execute details of their assignment," Tomlin said. "They need to make the other guys in the huddle very comfortable with their ability to execute."

Interestingly, Parker tried to deflect some of the heat, saying he was so hard on Mendenhall last week it might have been distracting.

"That's probably the reason he was making the mistakes," Parker said. "Coach holds each and every one of us to a high standard and expects us all to perform like professionals in practice."

The Steelers need to see more in games, too. So far, Mendenhall has gained only 107 yards in seven games during his short career. This season, the normally reliable Steelers running game is 27th in the NFL.

"It's frustrating, you want to take advantage of opportunities," Mendenhall said. "You want to prove to the team and the organization what you can do and I wasn't able to do that last week, so I'm looking forward to this week."