SANTA CLARA, Calif. (AP) New right tackle Erik Pears is doing all he can to fit into the 49ers huddle.

The 6-foot-8 Pears has a big void to fill after former starter Anthony Davis, 25, unexpectedly retired in June. The 49ers signed Pears in March to a two-year deal, thinking the 10-year veteran would back up both Davis and left tackle Joe Staley, a duo once considered one of the best in the league.

San Francisco heads into the new season expecting new starters at four of the five offensive line positions, with only two players remaining from the line that reached the Super Bowl in 2013. Staley will stay at left tackle, while Alex Boone is earmarked to shift from right guard to left guard, replacing Pro Bowler Mike Iupati, who signed with the Arizona Cardinals.

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Turnover has been a theme for the 49ers this offseason, after parting with head coach Jim Harbaugh and seeing a number of key veterans leave, including running back Frank Gore, defensive end Justin Smith and linebacker Patrick Willis.

The turnover has lowered outside expectations, fueling Pears and other new members of the 49ers' offensive line.

''You got to have that chip on your shoulder, got to have that edge to you,'' said Pears. ''And if you're not, and you get a little soft, you're going to get taken advantage of.''

A starting role won't be new for Pears, who started 44 games over the last four seasons with the Buffalo Bills. He played right guard last season for the first time in his career, but is more comfortable at tackle.

Throughout training camp and one preseason game, the 49ers have seen enough of Pears to feel confident about his insertion into the starting lineup.

''I think just last week alone, you got to see a preview of it,'' quarterback Colin Kaepernick said. ''We had very clean pockets, great pass protection. I'm excited about our offensive line and what they bring to the table.''

New head coach Jim Tomsula had Pears on his radar when they were both in NFL Europe in 2005 and 2006. Tomsula was the defensive coordinator for the Berlin Thunder and the head coach of the Rhein Fire while Pears played for the Cologne Centurions.

''He's one of those tough-nut Colorado dudes that climbed out of some, either got off a horse or climbed out of a mine,'' Tomsula said. ''(He) doesn't say anything, got his wife and four kids and that's about it. He's got that and football. So, he's my type of guy.''

With three spots along the line solidified, competitions are ongoing for center and right guard. Four-year veteran Joe Looney has received most of the practice reps at center, while second-year player Marcus Martin has played right guard. Martin has also worked at center, giving Brandon Thomas time at right guard.

Thomas missed all of last season while recovering from a torn ACL suffered leading up to the 2014 draft, when San Francisco selected him with a third-round pick.

The 49ers on Tuesday traded tight end Asante Cleveland to the New England Patriots for help along the offensive line, getting Jordan Devey, who made four starts at guard in 2014.

Devey, 27, signed with the Baltimore Ravens as an undrafted free agent in 2013, before moving on to the Patriots' practice squad later that year. Tomsula said Devey will work at both guard and tackle spots.

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