49ers coach Mike Singletary plans to give reserve running backs Brian Westbrook and Anthony Dixon more carries. San Francisco's Frank Gore has been one of the most used players in the NFL this season.

Mike Johnson said he wouldn't "hide" Troy Smith -- meaning, presumably, that Frank Gore won't get 42 carries Sunday - but acknowledged the playbook will have to be pared back. "He's a going in there and doing everything he needs to do," left tackle Joe Staley said. "We're just trying to make it as simple as possible for him." "I'm still trying to figure out some of the things that he does well," Johnson said. "Watching him practice and now that I have a chance to see what he can do (I can) put a game plan together ... I get three days to kind of see what he does well."

49ers quarterback Alex Smith will miss Sunday's game against the Broncos with a sprained left shoulder. Troy Smith will start in his place. "Troy Smith gives us a good opportunity to win this game," San Francisco coach Mike Singletary said. "He has enough of the offense to play." Alex Smith was injured on a sack in the third quarter of last Sunday's 23-20 loss to the Panthers.

It appears as though 49ers coach Mike Singletary is safe for the remainder of the season. San Francisco has started the season 1-6, but owner Jed York told the Sacramento Bee that he will stick with Singletary for the season. York disputed reports that 49ers executives were sour on Singletary following the team's 23-20 loss to the Panthers on Sunday. "We were grumbling because we lost the game," York said. "I think we grumble any time we lose a game."

The owners of the 49ers, John and Jed York, privately expressed displeasure about coach Mike Singletary following the team's sixth loss in seven games on Sunday, according to a team source. "There were some grumbles from the owners about bad coaching," the source said, according to a report by CSNBayArea.com. Singletary was signed to a four-year contract after guiding the 49ers to a 5-4 finish in 2008 as the interim coach.

49ers quarterback Alex Smith suffered an injury to his left shoulder on Sunday against the Panthers. Carolina's Charles Johnson landed on Smith's shoulder and the quarterback is worried that the injury might be similar to the one that cut his 2007 season short. Smith plans to fly to London with the team and have an MRI there. "It's definitely the AC, I think. It's very similar," Smith said, referring to the acromioclavicular joint that's sometimes called a separated shoulder. "But I don't know to what I extent. There's not really much to say right now."

The 49ers haven't used Brian Westbrook as much as many expected this season and starting running back Frank Gore appears to be the reason. "Frank Gore doesn't like to come out of the game," offensive coordinator Mike Johnson said. "He's a warrior; he likes to go." Through six games, Gore is fourth in the NFL with 116 rushes and his 33 catches are the most for a running back. He ranks second with 149 offensive touches and 755 yards from scrimmage. "Like I told my coach, I'll take a breather when I get tired," Gore said. "They've never told me to take a blow."

Patrick Willis has struggled to make the same kind of impact he has in past seasons. "I remember there were times when I could just stack and run and ... most of the times you never get touched," Willis said Wednesday. "Now, you're starting to feel it from every angle. They say, 'We have to put a hat on one of the best players at all times,' and they're doing that. "It's been a little frustrating not having the big plays that I've wanted to have."

The 49ers now expect their new stadium in Santa Clara to be finished in 2015, not 2014 as originally intended. The 49ers are looking for a loan of approximately $150 million from the NFL, which is currently in limbo. "I think '15 is a more realistic date just looking at the way the union negotiations are going," said Jed York. "I don't think with where we are today - we need to make decisions fairly quickly. Obviously, if we get something done soon, we could hopefully pull the trigger and get going on a design development that could get us to where we need to be for a '14 opening. But it's really a direct impact for financing and the NFL making an investment in the stadium at this point. Absent a labor deal, I just think that's going to be very, very difficult."

49ers coach Mike Singletary is downplaying the team's assumed interest in Chargers linebacker Shawn Merriman. Singletary says he likes the team's four-man rotation of outside linebackers. "I think they're doing a good job," Singletary said. "I think they're applying pressure, they're winning some of the one-on-one battles. I think they're doing a good job overall." The Chargers placed Merriman on the injured reserve list with a calf injury last week. When healthy, they will release him.