Running back Frank Gore not only likes the 49ers revamped offense, he envisions quarterback Alex Smith thriving in the detail-oriented scheme.

“You can tell the (offense’s) energy is different. You can see it in Alex,” Gore said Tuesday. “He looks really confident. He’s able to go. … Alex is going to be really good in this offense.”

Smith also expressed optimism a day earlier about the 49ers’ return to the West Coast offense system. One reason: Having a capable running back like Gore.

Said Smith: “Checking the ball down is kind of the epicenter of the West Coast offense — hitting backs quick, getting them the ball in space and letting them run.”

Gore has not played in an exhibition opener since 2008, but he might do so Friday night when the 49ers visit New Orleans. Coach Jim Harbaugh has said he wants Gore to get a few touches in the opener, and Gore is willing to partake in the offense’s unveiling.

“I know Coach doesn’t like me saying this, but on the offensive side of the ball, everybody is on the same page,” Gore said. “When you watch the film, man, it just looks different. Everybody knows what they’re doing. They’re flying around, motioning fast. It’s not boring.”

The 49ers offense ranked 24th last season during a 6-10 campaign.

Safety Dashon Goldson showed up in sweats to watch the final 45 minutes of Tuesday’s practice. Goldson, who’s started every game the past two seasons, agreed Monday to re-sign with the club on a reported one-year, $2 million deal. He joins a crowded secondary that includes recently acquired veterans Donte Whitner and Madieu Williams, who have practiced with the first-string unit. Whitner had two interceptions Tuesday. “We’ve got good competition back there, and (Goldson) will be part of that competition,” defensive coordinator Vic Fangio said. “We’ve become more athletic, more experienced, and just generally have uplifted and set the bar higher there on our talent level back there.” Reggie Smith, a part-time starter last season, underwent surgery on a torn meniscus Monday and is expected to be sidelined a few weeks.

Left tackle Joe Staley returned to practice Tuesday. He missed Monday’s session with an undisclosed injury that forced him out of Saturday’s practice.

Left guard Mike Iupati (biceps) did not participate in team drills. Rookie Daniel Kilgore replaced Iupati on the first-team offense.

Fangio said the 49ers have no intention of converting safety Taylor Mays into a linebacker, fearing potential mismatches against bigger tight ends and offensive tackles.

Although Harbaugh is projecting offensive starters to play 20 snaps Friday, Fangio said defensive assignments will vary per individual.

Cornerbacks Shawntae Spencer and Tarell Brown also have not returned from injury. Backup defensive tackle Ian Williams appeared to sustain a slight head or neck injury and was slow to leave the field.