Offseason free-agent acquisition Justin Hartwig will start Thursday night against the Buffalo Bills in Toronto after last season's starter, Sean Mahan, started the preseason opener against Philadelphia last week.
"I'd like to have it solved yesterday," Tomlin said Tuesday. "But you don't always get what you want. We'll have clarity, certainly, when we do make that decision."
Mahan-Hartwig is the hottest competition for a Pittsburgh starting spot. The only other clear-cut battle is at punter, where veterans Paul Ernster and Mitch Berger will each get equal opportunities to punt in the final three preseason games until Tomlin decides on a replacement for Daniel Sepulveda, who is out for the season after knee surgery.
"It's running its course," Tomlin said of the center competition. "We're going into the game looking at the quality and cohesiveness of the (offensive line) unit. The sooner we start evaluating, the better."
Polamalu has been on the physically unable to perform list all through training camp with a hamstring injury, while Townsend is being held out as a precaution due to a sore groin.
The Steelers signed former Jacksonville Jaguars starter Byron Leftwich on Sunday to replace Batch. Tomlin said he expects Leftwich to play extensively despite having only three days of practice with the team.
Tomlin said the first-team offense and defense will play more than they did in the 16-10 win over the Eagles, which was only one or two series.
"We'll really be focusing on things that are not talent oriented, and more on things that are cohesion oriented," Tomlin said. "We're looking for perfection from an assignment standpoint."
Copyright 2008 by The Associated Press