To be fair to each running back, both the Jets and Steelers have absolutely awesome run defenses, and I don't expect anyone to top 80 yards in this game.
Mendenhall did not have the statistical day he wanted against the Baltimore Ravens, but he did score the game winning touchdown with a second (or third, or fourth) effort against a tough defense.
Rashard is going to need to get his motor running early and often to prevent the great New York defense from blanketing receivers like they did against New England. If Mendenhall can get going early, the Jets are going to have to respect the run and the Steelers can use the playaction plays that they love so very, very much.
Tomlinson, on the other hand, is in a completely different point in his career. Four years ago, LaDainian would have been the factor in this game. This year, however, he's averaging only about 60 yards per game, and his touchdown numbers have been cut in half from last year.
Make no mistake, however, Tomlinson is still definitely a threat. His pass-catching ability out of the backfield has big play potential, and he can still turn on the jets (har-har) when he's in the open field.
Shonn Greene is not the pass catcher than LT is and tends to run a bit more between the tackles. He's a pretty standard running back in the NFL, so don't expect too much out of the guy who averaged 50 yards per game in the regular season.
The sad part is, I don't think any of these guys is going to have a day to remember because, as they say, no one runs on the Steelers or the Jets.