Alex Smith has the NFL's third-best passer rating. He didn't get that by buckling in the face of adversity, such as fourth-quarter deficits, during the 49ers' 4-1 start.
Smith went about practice as usual Wednesday, even though his targets didn't include opening-day starters Joshua Morgan and Braylon Edwards.
"Whether you like it or not, you don't have a choice. The next guy has to step up," Smith said. "We've got to keep going."
Morgan is gone for the season, having been placed on injured reserve after breaking his lower right leg in Sunday's 48-3 rout of Tampa Bay.
Edwards isn't expected back from knee surgery until Oct. 30, a week after the 49ers' bye. He didn't practice Wednesday and likely will miss Sunday's marquee matchup between the visiting 49ers and his hometown Detroit Lions (5-0).
That doesn't bode well for the 49ers' passing attack, which ranks 29th in the 32-team NFL despite encouraging efforts in the current three-game winning streak.
Smith is not flinching, neither at the lack of proven wideouts nor the unexpected magnitude of Sunday's game. What's more, Smith almost took exception to the notion that his next game is more meaningful than the 59 others he's played in his No. 11 uniform.
"Every time you strap on that helmet, every time you put the shoulder pads on, and you walk down those lines onto the field, I mean, it's enough as it is," said Smith, who sports a 104.1 passer rating. "You're playing
"All of a sudden, (regardless) of the two teams' records, you're still playing a football game and trying to win."
Sunday's win -- the franchise's most lopsided overall since a 55-10 demolition of Denver in Super Bowl XXIV -- came at the expense of Morgan's right ankle. Screws were surgically inserted to stabilize the fracture, an injury that occurred when he got tackled at the 1-yard line after a 19-yard catch with just over four minutes left.
Ted Ginn replaced Morgan as a starter on this week's initial depth chart. Michael Crabtree is the other starting wide receiver. Kyle Williams likely will be the No. 3 receiver, although the 49ers will probably deploy two and three tight ends to boost their receiving options and enhance Smith's protection against a fierce Lions defense.
Although Ginn has been electric on punt and kickoff returns, he has failed to catch a pass in four of five games. He had four receptions for 38 yards in a Sept. 18 overtime loss to Dallas.
"No matter who was in the lineup, we were all getting our fair share of looks," Ginn said. "(Morgan's exit) gives everybody else a greater opportunity to do a little bit better, a little bit more. We'll go out and seize the opportunity and push forward."
Morgan started all five games and led the wide receiving corps with 15 catches for 220 yards and a touchdown. Although Morgan is slated to become an unrestricted free agent, coach Jim Harbaugh said it will be a "priority" to re-sign Morgan.
Taking Morgan's roster spot is Brett Swain, who landed a one-year contract after Tuesday's audition. He spent the past three seasons with Green Bay. Also, a third wide receiver was added to the practice squad: rookie Kerry Taylor, whose uncle is former 49ers receiver John Taylor.
Whoever his targets, Smith is letting Harbaugh's system dictate where to throw the ball. Smith has completed 65.9 percent of his passes (83 of 126) for 965 yards and seven touchdowns. He's had two turnovers: one interception, one lost fumble.
Smith was 11 of 19 for 170 yards and three TDs against Tampa Bay, earning him the Samsung Next Level Player of the Week award.
Is this similar to how he ran Utah's offense before being drafted No. 1 overall in 2005?
"Schematically no," Smith said. "The one thing, maybe, is the same feeling I had is that I really feel I'm doing less. I really feel I'm playing within the system, doing my job, trying to make the plays when they're there to be made and not forcing anything.
"That's the way I felt in college."
Smith went 21-1 as the Utes starter. So far this season, he has only one loss, too.
For more on the 49ers, see Cam Inman's Hot Read blog at blogs.mercurynews.com/49ers.