"I don't know if I'd say surprised. I don't know if I was anticipating it, either," Smith said Monday after getting the news from coach Mike Singletary. "It's the opportunity I've been waiting for; happy."
Singletary made the announcement Monday after also sitting down with Shaun Hill, who was benched after the first half of the Niners' 24-21 loss at Houston on Sunday.
Smith, who hadn't played in nearly two years, came in and gave the offense a much-needed jolt of energy and efficiency, and he nearly led San Francisco (3-3) back from a 21-0 deficit.
"As far as will Shaun Hill be back and all this other stuff, we're not going to be a flavor-of-the-month kind of thing where, 'Let's see, this guy will be this week, this guy will be next week," Singletary said. "I wanted to make the decision based upon who I feel gives us the best chance to win."
Smith completed his first six passes and finished 15 of 22 for 206 yards and three touchdown passes to tight end Vernon Davis. Davis is the first 49er since Terrell Owens in 2001 to have three TD catches in a game.
The 49ers play at Indianapolis on Sunday, coincidentally the same team Smith debuted against in 2005. This will be his first start since Nov. 12, 2007.
"I think right now overall Alex Smith really just kind of fit the bill in terms of doing the things that we need to get done," Singletary said.
Smith, the No. 1 draft pick out of Utah in 2005, missed all of last season after reinjuring his surgically repaired throwing shoulder three days before the season opener. He was set to be the backup to J.T. O'Sullivan.
When this season began, Singletary decided Hill was the best man behind center for San Francisco, a franchise desperate to end a streak of six straight losing seasons.
The 25-year-old Smith has shown signs in practice of being more than ready to handle this role. It was Smith who spent several days during the recent bye week working with receiver and top draft pick Michael Crabtree to get him up to speed on the offense before his debut against the Texans. Crabtree, who finally signed his six-year deal Oct. 7, had five catches in an impressive first game.
Singletary, who insisted his decision wasn't "premeditated," sensed a positive vibe from everybody -- save maybe for Hill -- with Smith's calm, confidence presence on the field. Not that Singletary didn't have a feeling Smith could take charge of his unit and lead the team again after all he's been through.
Singletary has seen Smith's strides in recent months.
"Let him develop that hunger, let him get excited, 'Well if I get an opportunity again.' Let him develop some confidence, 'I think I can do that,'" Singletary said of the time Smith needed to evolve. "Rather than just putting him in at the beginning of the season and if you don't have success right away, then it's, 'Same old Alex.' I don't think it's the same old Alex. I think Alex has matured, I think he's grown and I think he's ready to play. We're going to find out. We'll find out next week."
Not that Smith needed any more motivation: He knew he'd better take advantage if he ever got another opportunity. He knows he's done more to earn his spot this time around than as a rookie.
He doesn't plan to change now. And he no longer thinks about his shoulder.
"I've been out for two years now. I don't know if I was getting any hungrier," Smith said. "I've kind of been waiting. It's been frustrating and I've got a chance to get back out there and make the most of it."
Hill began the season as a starter for the first time in his eight-year NFL career and led the 49ers to a 3-1 start. He lost his job Monday a year to the day after Singletary benched O'Sullivan in favor of Hill during the coach's debut against the Seahawks.
Hill struggled in the first half Sunday, when San Francisco had only 50 total yards and he was 6 of 11 for 45 yards.
"It's frustrating. It's upsetting," Hill said. "It's not going to keep me down. Nothing ever has, nothing ever will. It's the same thing he went through and it didn't hold him down, either."
Texans defensive end Mario Williams said he didn't know who Smith was when the QB came out to start the second half. That's how far he had fallen off the NFL radar.
"When I look at Alex, I really didn't know what we were going to get when he went in," Singletary said. "I was hoping we'd get what we've seen out here in practice, and that's what we got. I was excited to see that, the excitement and the enthusiasm on the sideline, the excitement and enthusiasm on the defensive side of the ball, the receivers, the running backs, everybody."