With Joe Flacco still nursing a tweaked back, coach John Harbaugh said Mallett will start and play "pretty extensively" on Thursday.
"How much that ends up being probably will be determined," Harbaugh said, via the Baltimore Sun's Jeff Zrebiec. "We'll have a plan, but during the game, I'll probably have to get a sense of that and how I feel about it. But yes, it's an opportunity for Ryan to get ready.
"He's had that chance before last year in the offseason before Joe got back for training camp. Those reps are really huge for a quarterback. He'll want to make the most of all those reps with the ones and we'll just see where it goes from there."
Thursday will be a chance for the veteran backup to shut down the critics. If he fails, it opens to door to a deluge of calls for the team to sign Kaepernick -- even if Ozzie Newsome is hamstrung by the salary cap at this point.
After his disastrous opening to camp, Mallett has reportedly calmed down in practices. Despite the positive trend, the 29-year-old quarterback knows Thursday is a pivotal point in the process.
"Every day, I'm just trying to get better, trying to get in better sync with my team, better timing," Mallett said when asked about the talk about Flacco's status and Kaepernick possibly being signed. "I've got tunnel vision. I'm not really worried about what's going on outside of this building.
"It's training camp. I think it's practice eight or nine. So every day, we're just trying to get better, trying to get more cohesive, get our timing down. So I think we're coming along."
Thursday night all eyes will be on Mallett. If he lights up Washington, the talk of signing Kaepernick could melt away. If he plays poorly, he could lose his job in short order.