The following is the fifth of nine position previews in advance of training camp.

When the Bears step on the practice field for the first time at training camp next week, they'll do so with the same five offensive linemen that started all 16 games last season.

In 2013, the Bears offensive line ranked second in the NFL with 455 points.

General manager Phil Emery revamped the unit a year ago and it served as a catalyst for a record-breaking offense in 2013. Last offseason the Bears signed left tackle Jermon Bushrod and left guard Matt Slauson in free agency and drafted right guard Kyle Long and right tackle Jordan Mills.

The four newcomers gelled quickly with veteran center Roberto Garza, ultimately helping the Bears rank second in the NFL with 445 points and set franchise records with 6,109 total yards, 4,450 passing yards, 32 passing touchdowns, a 96.9 passer rating and 344 first downs.

This offseason the Bears kept the unit intact by re-signing Garza and Slauson.

"To be able to bring them back again, continue to progress and add to the system is certainly a benefit," said coach Marc Trestman.

"They're focused on trying to be the best offensive line they can be. They know they can get better. And we've got some new guys in the mix that are competing as well, not necessarily for starting positions but for positions on the team. So it's a positive thing."

During the offseason, the Bears re-signed top backups Eben Britton and Taylor Boggs and added free agent center/guard Brian de la Puenta, who spent the past three seasons with the Saints, starting all 16 games each of the last two years and 12 of 16 games played in 2011. Britton is especially valuable, having frequently been utilized as a sixth offensive lineman last year.

The cohesiveness the line developed last season helped the Bears allow only 30 sacks, tied for the fourth fewest in the NFL, and pave the way for Pro Bowl running back Matt Forte to rush for a career-high 1,339 yards, the most by any Bears player other than Hall of Famer Walter Payton.

Bushrod stabilized the line at the all-important left tackle position. He was selected to the 2013 USA Football All-Fundamentals Team, which honors NFL players who exhibit exemplary techniques for youth players to emulate.

Slauson was named to USA Today's "All-Joe" team, which honors unsung NFL players who have never been voted to a Pro Bowl.

One key to the line's success last year was the development of Long, who was voted to the Pro Bowl as a rookie after starting only five games at the Division I level in college.