Right guard Alex Boone takes "maybe three, four" snaps at the tackle position during a given week of practice. These are not a handful of plays that he enjoys, despite the fact that he still thinks of himself as capable of protecting the edge of the offensive line.
"If I'm a guard, I'd rather play guard," Boone said. "Why worry about so many other things?"
A less than ideal situation played out on Sunday afternoon at Candlestick Park: With Pro Bowl left tackle Joe Staley (right knee) going down during the 49ers first offensive drive of the team's 23-13 win over the visiting St. Louis Rams, Boone was shifted to Staley's spot.
Read: 49ers Beat up on Rams
With Boone protecting the quarterback's blindside, Colin Kaepernick was 19-of-28 passing for 275 yards and a touchdown. (In case you haven't heard, the 49ers are 12-0 when Kaepernick's passer rating reaches at least 90; he finished with a 111.5 mark.)
Another statistical sign of strong play: Rams defensive end Robert Quinn, who entered the game with an NFC-high 13 sacks, managed just three tackles. He was matched up with Boone at times.
"It is like riding a bike. I did it for eight years. Coming back home, it feels good," said Bone, who was his usual jovial, joking self postgame, about playing the tackle position he assumed in high school and college. "I still try to tell (coaches) I'm a tackle, but they say I'm too slow. That hurts my feelings.
"I just try to be a good soldier… On the off-chance that something like this happens, you have to be ready, and we were ready as an offensive line."
The absences of Staley and another Pro Bowler – left guard Mike Iupati (left knee) missed a second straight game – also forced reserves Adam Snyder and Joe Looney into extended action.
Snyder started at Iupati's left guard spot and, after Staley exited, Looney assumed Boone's right guard slot.
"I knew he was going to play like a man," Boone said of Looney, a second-year pro. "When he first came out there, we said hey, 'It's time to be a big boy.'
"It was a chippy game to start with, and we knew it was going to be like that. Knowing Joe, we knew he was ready."
Photo Gallery: 49ers vs. Rams
Boone called Looney's only noticeable mistake, a holding penalty that negated a Kaepernick scramble just before halftime, "rubbish."
"Hell of a performance, coming off the bench and just kicking some (butt)," Boone said. "Can't be more proud of the guy than that. I know he's going to be ready for this week."
The 49ers have long expressed confidence in Snyder, too, who reunited with the team this offseason because of his versatility. While both he and Looney can play multiple positions along the line, Snyder said he was given valuable instruction from Staley and Iupati on the intracacies of playing guard within the team's scheme.
"His leadership, between him and Mike tellings us what we're doing on the field, they're watching," Snyder said. "They see everything we see from a different perspective. Getting information from is good."
Looney added: "Everybody felt bad that Joe went down, but we had to focus on the game. It was the best thing to do for the guys that got hurt."
As for how long Staley could be out, there was no immediate answer, only speculation and reports employing unnamed sources.
"I don't want to make any rush judgment," Jim Harbaugh said, "or repeat anything until the tests have been run."
If Staley misses as much time as Iupati already has, Looney could be in line for his first NFL start. He made his NFL debut in Week 12 at Washington.
"If that happens, then it does," Looney said. "I'm going to continue to look at guys like Boone and Mike, and the film to continue to get better every week."
Snyder, too, could see his run as a starter continue.
"Those are big shoes to fill for us," he said, "but we're excited about the challenge and the opportunity to step up."