The sixth rookie to start for the Ravens this season, Smith will take over the offense after quarterbacking four series in the NFL.
"He's as ready as you're going to be as a rookie," coach Brian Billick said. "One thing I don't worry about is that he has a strong personality. You worry what happens if things get ugly with him and pressures ... but he will fight through whatever happens. He's a very strong-willed young man."
It's questionable whether Boller, who suffered the concussion last Sunday, can be the backup at Seattle. If he can't play Sunday, the Ravens would promote undrafted rookie Cullen Finnerty from the practice squad.
Because the Ravens have to be careful with Boller's head injury, Billick acknowledged that Smith could start the season finale against the Pittsburgh Steelers, too.
"Concussions are very unpredictable," Billick said. "I'm certainly not an expert, so I'll rely on the experts to say what and when that could change."
In two NFL appearances, Smith has completed eight of 16 passes for 82 yards. The 2006 Heisman winner and fifth-round draft pick has taken every snap with the starting offense this week in preparation for Sunday.
Smith said he brings intensity every week, but he understands this week of practice is different.
"At certain times, certain things need a little more focus," Smith said. "And when you're in a situation to start, you have to be incredibly focused."
But it took a notable occurrence for Smith to get the starting nod. This is the first time in Billick's nine seasons as coach that the Ravens have lost their top two quarterbacks to injury.
Asked whether he was surprised that happened this season, Billick said: "No. You can pretty much expect that."
The Ravens likely won't make a determination on Boller's status until after they take their six-hour flight to Seattle. Boller is having headaches and is sensitive to light.
"If they sign off on [Boller to be the backup], he knows enough of the game plan to go in and get us out of a game," Billick said. "But we're certainly not going to put him at risk."
If Boller can't play, the Ravens would go with Finnerty, who had a record-setting career at Division II Grand Valley State.
Finnerty was signed by the Ravens for their offseason camps but was cut before training camp when Drew Olson returned from NFL Europe. The Ravens signed Finnerty to the practice squad after they placed Steve McNair on injured reserve.
When the Ravens contacted him two weeks ago, Finnerty was taking a writing course to finish his degree.
"It's crazy," Finnerty said. "I never figured this situation would occur. Luckily, I've been preparing hard and staying ready."