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

After a disappointing 2019 season, the Bears are counting on a new position coach to help a veteran offensive line revert to the form it displayed in 2018.

Hired in January, Juan Castillo enters his 25th NFL season. He has coached with the Eagles (1995-2012), Ravens (2013-16) and Bills (2017-18), working with Bears coach Matt Nagy from 2008-12 on Andy Reid's staff in Philadelphia.

With Castillo as Eagles offensive line coach from 1998-2010, Philadelphia made nine playoff appearances and rushed for an average of 1,854 yards and 12 touchdowns per season. During his 13 seasons as Philadelphia's line coach, five different players combined to earn nine Pro Bowl invitations.

Castillo strongly believes in honing fundamentals through repetition.

"To be a good lineman, you have to be consistent," he said. "And the only way you become more consistent is by doing something over and over and over and over."

The Bears return veteran starters at four of five positions on their offensive line this year in left tackle Charles Leno Jr., left guard James Daniels, center Cody Whitehair and right tackle Bobby Massie.

Leno and Whitehair earned Pro Bowl honors in 2018 when the Bears won the NFC North title. But after the offense regressed in 2019, general manager Ryan Pace conceded at his postseason press conference that "we struggled in that area … and I think we know it starts up front with those guys."

When asked what accounted for last season's regression, Pace cited injuries to Massie and right guard Kyle Long, as well as the decision to flip-flop Whitehair and Daniels.

Bothered by a hip issue, Long did not play well early in the season before being placed on injured reserve Oct. 14. He was replaced by Rashaad Coward, a converted defensive lineman who had appeared in only one NFL game prior to the 2019 season.

Massie later sustained an ankle injury that forced him to miss the Bears' final five games. He was replaced by journeyman Cornelius Lucas.

Last offseason the Bears moved Whitehair from center—where he had played exclusively during his first three NFL seasons—to left guard while switching Daniels from left guard to center. Daniels started at left guard as a Bears rookie in 2018 but had played center during his final two seasons at Iowa in 2016-17.

After losing their fourth straight game to fall to 3-5, the Bears moved Whitehair and Daniels back to their previous positions and the offense performed better, leading to four wins in five games.

Castillo is confident that Daniels is capable of excelling at both guard and center.

"James Daniels is smart," Castillo said. "He's an athlete. He's going to be a good player whether he plays guard or center. If you're a really good guard, you'll be a good center because everything is a little tighter. With the length and the size that James has, I think he has a chance to be a very good guard. I think James has gotten a little bigger. I think he's going to come in about 10 pounds heavier than he was last year."

One of the most intriguing position battles in training camp and the preseason this summer figures to be for the starting right guard position. Free-agent acquisition Germain Ifedi will compete for the job with Coward and Alex Bars, among others.

Ifedi, 25, was selected by the Seahawks with the 31st pick in the first round of the 2016 draft out of Texas A&M. He started all 60 games he appeared in over the past four seasons, helping Seattle earn three playoff berths.

The 6-5, 325-pounder started 13 games at right guard as a rookie in 2016 before moving to right tackle in 2017. Over the past three seasons he has started 46 games at right tackle and one at right guard. The one at right guard came in the 2018 season finale when he replaced the injured D.J. Fluker.

Castillo likes Ifedi's size, toughness, desire and work ethic.

"I am excited about him," Castillo said. "He comes from a winning program. He knows how to work. But really there are some things he knew he needed to work on. We're going to work on teaching him to stay square. And the important thing is that Germain has taken it upon himself to work his [butt] off, to learn how to stay square in pass protection. And I'm excited for everyone to be able to see that, and I think he's excited for that because I think that's something that he knew he needed to work on and he's been working his [butt] off on it."

In addition to signing Ifedi, the Bears also added depth and competition to their offensive line during the offseason by inking free agent Jason Spriggs and selecting Lachavious Simmons and Arlington Hambright in the seventh round of the draft.

Spriggs was chosen by the Packers in the second round of the 2016 draft out of Indiana. He appeared in 36 games with nine starts over three seasons in Green Bay from 2016-18 before sitting out the 2019 campaign with an injury. He started two games at right guard as a rookie in 2016 and seven contests at right tackle in 2017-18.

Hambright started all 12 games at left tackle last season as a graduate student at Colorado and was named honorable mention All-Pac 12 by the league's coaches. He transferred to Colorado after earning his undergraduate degree at Oklahoma State. Simmons played every offensive line position except center during four seasons at Tennessee State, appearing in 41 games.