Troy Smith is what you would call a "dual-threat quarterback." A dual-threat quarterback is one who has the the ability to elude or run past defender which creates an additional threat, allowing greater flexibility in the team's passing and running game. In short, if the receiving options are slim-pickings on that particular play, a dual-threat quarterback can tuck the ball down and make some plays with his feet.
Not only can he pick up yardage, but he can cause exceptional worry in a defense when he "looks," like he's going to make a break for it, which can often free up a receiving target when a linebacker or defensive back over-pursues to account for the possibility of the quarterback running the ball.
That brief and possibly unnecessary explanation aside, Troy Smith is a dual-threat quarterback. Alex Smith falls somewhere in between the two. He can use his legs, and I'm sure defenses make note of that fact, but he's not a guy that defenses generally spy. We've yet to see how Troy Smith will be utilized for the Niners, but considering the holes in Denver's defense, I imagine he'll have some opportunities to make plays with his feet.
Troy hasn't been big on running since his college days, but then again, he hasn't had much NFL action. In his career, he's played in fourteen games and has 109 total rushing yards, nothing to get overly excited about. He did have 1,197 rushing yards in college, however. That same college career saw him wildly successful in the "option," based offense. That's one thing I think we can see tomorrow, a variant of an option play. Jump.
This team is 1-6, why not? Basically, the "all-out," option play the 49ers would run will theoretically consist of Troy Smith at quarterback, with Frank Gore behind him or to his side, with possibly Brian Westbrook also behind him or to his side. Brian Westbrook would kick outside for a pitch, Frank Gore would go up the middle for a dive, or Troy Smith could tuck it and run from the get-go. He has the "option," to decide which of those would be best.
That's just some of the creativity we could see out of Troy Smith and Mike Johnson. There's a reason the option isn't used with regularity in the NFL, but when you're in the business of exploiting certain defenses, being deceptive with the ball is where they want to go. Denver's defense isn't the laughing stock of the NFL, but it regressed last week against the Raiders, and if there's a place to strike, it's the still-fresh wound.
One last thing to note: even if the 49ers decline to run to the option play, we could still see Troy Smith using his mobility more than one might think. With the 49ers giving him a limited playbook with minimal ability to audible out of certain plays, the options for him won't be numerous. So when he senses that things won't go his way, he might be given the go-ahead to tuck it and run. Worth thinking about.