Smith bruised his chest on the opening drive of Saturday's 37-30 preseason win at the Dallas Cowboys. Harbaugh said earlier in the week that he anticipated Smith playing in the third preseason game. But the Ravens are taking the cautious route with Smith.
"He probably could play if it was a regular-season game," Harbaugh said.
Harbaugh also ruled out cornerbacks Lardarius Webb (back) and Asa Jackson (ankle). It's interesting to note that Harbaugh said his top three cornerbacks wouldn't play, which insinuates that Jackson is above Chykie Brown on the depth chart.
With all of those cornerbacks sidelined, the Ravens will start Brown and Dominique Franks and use Terrence Brooks as the nickelback. They'll have to match up against the Redskins wide receivers DeSean Jackson and Pierre Garcon.
"It's going to be an opportunity for those guys to go against the best for a long period of time," Harbaugh said. "It's going to be a good chance to evaluate where we're at and give those guys an opportunity to prove they can play with the best."