SANTA CLARA, Calif. -- The sights and sounds of the typical NFL training camp aren't quite the same with Jim Harbaugh running things for the San Francisco 49ers.

The digital timers commonly used to break practices into periods do not exist there. The air horns NFL teams traditionally fire to signal transitions between periods never sound. Staffers generally responsible for managing such things can focus their attention elsewhere.

Harbaugh tracks it all himself, keeping the time in his head, sometimes without even consulting a watch. The only whistle at practice belongs to him. Harbaugh blows it when he's ready for a new period to begin. If there's a bad snap or miscue, too bad. It's on to the next play. Corrections can wait until the end of practice.

The devices teams have traditionally used to ensure practices move along on schedule would actually make it tougher for Harbaugh to push the tempo to his liking. In interviews right after practice, Harbaugh sometimes comes off as distracted, as though his mind is racing through the two-minute scenarios that helped him earn the nickname "Captain Comeback" as a player. Practice ended 12 minutes early Wednesday.

"There is no wasted time," said left tackle Joe Staley, a first-round draft choice in 2007. "I think that is carrying over to the mindset. This isn't just fun. This is our job."

Players accustomed to two-hour camp breaks at midday under other coaches now scarcely have any down time at all. They're in the building by 6:30 each morning and out by 9:30 each night. They do not leave the premises in the interim.

There's no more whining to a wife or girlfriend over lunch about the rigors of camp. Cupcaking, as Harbaugh calls it.

"You are always thinking football," said tight end Delanie Walker, who has been with the team since 2006. "That is what we needed. We needed to think football because we have a young team and they don't understand that this league is tough and if you lose focus on what we have to accomplish, that can hurt you."

THREE HOT ISSUES

Coach Jim Harbaugh elected to bring Alex Smith back as the starting QB despite his less-than-stellar track record. AP Photo/Paul Sakuma

1. Can Harbaugh fix Alex Smith? It's a tantalizing question for those still hopeful Smith might develop into a viable starter. There's no doubt Harbaugh brings more offensive expertise to the job than his recent predecessors did. Smith has embraced learning from a coach with Harbaugh's understanding of the position. One veteran player said Smith never lost the locker room, in part because teammates knew the deck was stacked against him. "It's hard to describe what it's been like in the past as far as schematics go and how difficult it is to deal with, the situations we're put in as players," the player said. "I think with this new coaching staff, they want to put you in position to be successful. It's not just, 'We're going to run power because we're physical and we don't care if they have nine guys in the box.' Look at all the weapons we have, put them with our coaching staff and I think he's going to be productive." As always, though, it comes down to whether Smith can get it done during games. He's usually said the right things and taken the right approach during the offseason.

2. Why so many changes on defense? The 49ers absorbed criticism early in free agency as players departed and the organization took a measured approach to lining up replacements. Defensive starters Takeo Spikes, Aubrayo Franklin, Manny Lawson and Nate Clements did not return. Another defensive starter, Dashon Goldson, lingered on the market before taking a one-year deal to return. Where was the urgency? It's helpful to remember the team's general manager, Trent Baalke, experienced firsthand the risks associated with aggressive free-agent spending while working for the Washington Redskins from 2001-04. And with a new defensive coordinator in Vic Fangio, priorities changed. Franklin was a pure two-gapping nose tackle. His replacement, Isaac Sopoaga, might be better suited for Fangio's slanting 3-4 scheme featuring fire-zone tactics in doses. The 49ers see the middle of their defense as even stronger following free agency. They love their depth at safety and are expecting a breakout year from NaVorro Bowman at inside linebacker next to Patrick Willis.

3. Can the 49ers 'buy in' yet again? The 49ers are on their third head coach and seventh offensive coordinator since 2005. Most recent seasons have begun with fresh promise, followed by disappointment and even disillusionment. Here comes Harbaugh, full of energy, pumping up hopes once again. I wondered whether players would be too jaded to invest fully from the beginning. "It's not about Harbaugh getting me to buy in again," Pro Bowl tight end Vernon Davis said. "It's not about him. It's about the team wanting to win games. ... There is nothing anybody can do to get me to be involved. I am going to be involved whether they like it or not, because that is what I do. You go through adversity, but you have to keep believing."

BIGGEST SURPRISE

Dashon Golson re-signed with the 49ers for a one-year deal after testing the free-agency waters. Mark J. Rebilas/US Presswire

Dashon Goldson's return. The 49ers suddenly have options at safety after Goldson, a 2010 starter, returned on a one-year deal for $2 million. The situation played out perfectly for the team. San Francisco signed Donte Whitner and Madieu Williams in free agency while Goldson tested a soft market. Reggie Smith was having a good camp before suffering a knee injury that will keep him out for at least a couple of weeks. The team still has Taylor Mays as well, at least for now. Whitner (strong) and Goldson (free) project as the likely starters unless Reggie Smith can get healthy enough to make another run at the job before the season. Goldson has plenty of motivation entering a contract year. Whitner started quickly and wore down with Buffalo last season. The 49ers' offense can help him out by sustaining drives and giving the defense some rest.

BIGGEST DISAPPOINTMENT

Michael Crabtree's injury. This marks the third lost offseason in three years for the player San Francisco drafted 10th overall in 2009. Crabtree missed camp and the first six regular-season weeks of his rookie season during a contract dispute. A neck injury prevented him from playing in a single exhibition game last summer. A foot injury has prevented Crabtree from practicing even once at camp this season. The 49ers protected themselves by signing Braylon Edwards to a one-year deal, but they need more in return from their investment in Crabtree.

OBSERVATION DECK