Ben Roethlisberger will rest for the first preseason game, and primary backup Landry Jones is dealing with an abdominal injury.
"One man's misfortune is another man's opportunity," Tomlin said. "I know [Dobbs is] excited about it. I know I'm excited about watching him play the quarterback position in that group."
The Steelers will make judgments about the availability of other players over the next two days. More than a dozen players have missed practice time due to injuries, including left tackle Alejandro Villanueva, who's being evaluated for a concussion.
Tomlin wants to see Dobbs' game-day demeanor and communication with coaches and players.
Dobbs, who earned an aerospace engineering degree from the University of Tennessee in May, said he's focused on those areas during camp.
"You're a communicator. You have to understand, you have to say it with confidence and speak clearly and loudly for your team to hear," Dobbs, a fourth-round pick, said after Wednesday's walk-through. "You have to own the position. You have to own the playbook."
Tomlin considers Dobbs a "bright-eyed, willing worker" who learns from mistakes. But he wants to see what Dobbs can do in an NFL stadium, in live action.
"At that position, you're defined by how you perform in certain circumstances," Tomlin said. "It will be good to get him in that stadium on Friday and watch him, in terms of putting his skills on display."
In other Steelers news, Tomlin said he has remained in contact with running back Le'Veon Bell as he trains in South Florida. Bell has yet to report to camp and sign his $12.1 million franchise tender.
Tomlin added he doesn't have an update on Bell's status. All signs point to a late-August arrival for Bell.