SANTA CLARA, Calif. (AP) Going into the second week of camp, the San Francisco 49ers are still addressing growing pains on offense.

For second-year offensive lineman Marcus Martin, that has meant learning a position he hasn't played since high school.

For veteran wide receiver Torrey Smith, that has meant adjusting to the velocity of Colin Kaepernick's passes and getting on the same page with his new quarterback.

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''It's always going to be a work in progress,'' Smith said Saturday. ''I think we're going in the right direction, fixing the mistakes. That's what the first week of camp is about, really camp in general. We're doing a great job learning from mistakes, and you can see the growth.''

While Kaepernick works to develop a consistent connection with his speedy new wide receiver, there is plenty of growth taking place along the revamped line in front of him.

Martin is San Francisco's new starting right guard, and his situation is an example of all the change taking place on a 49ers offense that lost four key veteran starters during the offseason and is operating under the direction of new coordinator Geep Chryst.

That change has led to some sloppy moments in training camp for the unit and players getting accustomed to new surroundings and new teammates. But as the 49ers began their second week of camp, things are beginning to fall into place.

''What people don't understand is this is practice, this is training camp, and the point is to learn from your mistakes,'' Martin said. ''Every day is not going to be a perfect day. As you've seen, we've practiced on things we need to execute and we improve. That's the whole point of this process, to come out and get better.''

That improvement is beginning to surface on an offensive line that likely will have all four positions to the right of Pro Bowl left tackle Joe Staley manned by new starters when the 49ers begin the preseason next week against the Texans in Houston.

As a rookie last season, Martin started eight of San Francisco's final nine games at center after replacing injured Daniel Kilgore in November. The Niners are moving Martin to right guard this summer to replace Alex Boone, who is being shifted to left guard next to Staley to replace Mike Iupati.

''Marcus Martin is a really good center,'' 49ers coach Jim Tomsula said. ''And Marcus is becoming a really good guard. He's doing a really good job there now. That's why I'm not telling you who's playing where along that line. We've got to go with the best five. It's the sum of the parts. It's not one guy. They've got to be together.''

The other new starters lining up next to Martin are Joe Looney at center and Erik Pears at right tackle. Looney started one game at center last season and Pears joined the 49ers as a free agent during the offseason.

Martin's experience at center has helped him adapt to a position he never played in college as he works to get in sync on the right side with newcomer Pears, who has 58 starts at tackle.

''The switch is helping me be better as a player,'' Martin said. ''Being able to learn two positions makes me more valuable to the team, and at the end of the day, that's all I want to do, is help the team. Playing right guard, it's some growing pains, some things you have to get through, things you have to get used to. But the process has been going along pretty smoothly.''

Though it was most evident along the line, there were growing pains elsewhere on offense during the first week of camp. Smith, another newcomer, would be the first to admit it.

The 49ers signed Smith to a $40 million deal during the offseason to provide a deep threat for Kaepernick, an element that has been missing from San Francisco's offense for several seasons. But it's taking a while for Smith and Kaepernick to click.

''Yeah, we're definitely still getting stuff together,'' Smith said. ''When there's a play that happens, I always go over to him and say, `Hey, what were you thinking on this?' so we get on the same page about certain things.

''It's not that I feel I'm a speed demon or the fastest man in the world or anything, but sometimes I feel like, `I can run, bro - you can throw it out there, I'm going to go get if for you.' It's our first year working together, so it's on us to make it happen.''

NOTES: To fill Aldon Smith's roster spot, the 49ers singed outside linebacker Shawn Lemon, who was recently waived by the Pittsburgh Steelers. Lemon, 26, has spent time with four Canadian Football League teams, two Arena League teams and one Indoor League team. Lemon tied a CFL record with eight forced fumbles and had 13 sacks last season for the Grey Cup champion Calgary Stampeders. ... Due to problems with the sod at Levi's Stadium, the 49ers have moved Sunday's training camp session to practice fields at the adjacent team facility and canceled a scheduled public practice at the stadium. The team had issued more than 10,000 free tickets to fans online for the public session before issues with the field surfaced. ... DL Tank Carradine (illness), WR/KR Bruce Ellington (leg) and LB Phillip Wheeler (leg) where held out of practice.

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