SANTA CLARA, Calif. — Even before the first practice, the heat was on San Francisco 49ers quarterback Alex Smith.

Smith, who, in 2006, became the franchise's first quarterback to take every snap, watched from the sidelines injured in 2007 as veteran Shaun Hill took over.

Now, the two are in friendly competition for No. 1.

It's a consequential issue for the franchise, which selected Smith with the No. 1 overall pick in the 2005 NFL draft and then gave him a $49.5 million contract to lead the team into the future at the game's most pivotal position.

But Smith has mostly struggled. After making promising strides in his second season of 2006, his progress took a regressive detour during last year's injury-plagued and turmoil-filled season resulted in a 5-11 finish for a team that entered the season with playoff expectations.

Smith led the young 49ers to a 7-9 record and the edge of postseason contention. But he got off to a slow start under a new offensive coordinator (since fired) last year, then suffered a separated throwing shoulder in Week 4 that doomed his season.

Smith attempted a comeback a month after the injury, but he was obviously hampered by his injured wing while playing poorly in three starts. His third year ended there before he underwent season-ending shoulder surgery, opening the door for Hill to present a challenge to Smith's starting position this year.

Smith is attempting to answer a lot of questions this summer from those who have expected much more from a player of his draft pedigree.

"This is year No. 4 for me," Smith said. "There is enough talk about potential and capabilities. It's about coming out here now consistently playing well."

Smith looked sharp this spring and clearly is the front-runner at the position as camp begins. But the 49ers are obliged to give a long look at the surprising Hill, the seventh-year veteran who excelled when given the first opportunity of his career after both Smith and veteran backup Trent Dilfer were sidelined by injury last year.

Hill, who never has been much of an impressive practice player, had relatively astonishing success in the three games he played, particularly considering he never before had thrown a pass in a regular-season game during his first five NFL seasons. He went 2-0 as a starter, completing 68.4 percent of his passes with a quick, precise release and compiling a 101.3 passer rating.

That convinced the 49ers to unload an aging, ineffective Dilfer, who ultimately retired earlier this month. The team signed Hill to a contract extension early this year with the promise he'll get a legitimate shot at the starting job.

Another dynamic to the Smith/Hill competition is their openly amiable relationship. They work together, root for and support each other, and both say that will continue whoever gets the starting nod.

But while Smith says "I definitely try and take that role that it is my huddle and it has been mine for a few years now," Hill hardly is conceding that he sees Smith as the team's No. 1.

"We're competing," he said. "But when I'm competing against the defense, along with the 10 guys I'm playing with, I'm not competing against Alex. We're ultimately team players and we want what's best for this team. Whichever guy is playing better, he's going to be what's best for this team."

While some say it would be an admission of failure and setback for the organization if Smith isn't named the starter, Nolan said those issues won't be a factor in the final decision.

"The objective is to win games, so the best thing for the organization and everyone here is that the best man wins the job, first and foremost," Nolan said. "And, Alex might be the guy. But I'm pulling for both of them. We're about winning. We're not about favoritism."

So every day, every practice, becomes meaningful in the ongoing process. Smith and Hill will alternate with the first unit during team drills from practice to practice, with the 49ers planning a similar setup for exhibition games next month.

"It is definitely high stakes," Smith said. "Every single day is going to count. Every single day is going to be evaluated. There are only two weeks before our first (preseason) game. You have to come out here to play. You can't have an off day, or lack of focus, or anything like that."