"Flash forward to Baltimore on the 11th of September: Rashard Mendenhall bursts through a hole in the Steelers' line but is barreled backward by the Ravens' Ray Lewis. His ankle bends awkwardly. He is carted off the field, cringing in pain.

Mike Tomlin looks down his sideline and sends in ...

No easy answer, is there?

Well, the Steelers had better find one, sooner rather than later.

Mendenhall has been one part force, two parts workhorse the past two seasons, with 627 carries and 2,611 yards, including playoffs. That's the third-most carries in the NFL in that span. Yeah, he's 24 years young, tough, durable, and he holds onto the football more often than James Harrison thinks. But this is a grind not even Earl Campbell could sustain.

Not that anyone concerned will acknowledge it.

I asked Mendenhall about his workload yesterday at St. Vincent College, and he came back flatly: "That's part of the game, part of your job as a running back. I'm preparing to carry whatever load I'm given."

Kirby Wilson, the Steelers' running backs coach, shrugged it off, too: "He's fine. He's a young man. He's built for it, and we feel like he's a special runner. Why take him off the field?"

Why?

Where do I start?

In an era in which most teams have running back tandems — Baltimore, for instance, just added Ricky Williams to back up Ray Rice — Mendenhall has accounted for an alarming 62.7 percent of the Steelers' carries the past two seasons. Of the league's top 15 rushing teams last season, the Steelers, who ranked 10th, had the lowest-ranking No. 2 rusher in Isaac Redman with 247 yards."