BOURBONNAIS, Ill. — Chicago Bears cornerback Kyle Fuller and longtime Virginia Tech defensive coordinator Bud Foster have remained very close over the years. Their relationship started with Fuller's recruitment out of high school, grew stronger through four years together in college and they have remained close through Fuller's four NFL seasons.

"We've had a strong bond," Fuller told PFW on Tuesday, "and there's a lot of trust there."

It makes sense. The oldest Fuller brother, Vincent, played defensive back at Tech under Foster, followed by wide receiver Corey at Tech a few years later. Bringing home the family quartet were Kyle and youngest brother Kendall, who is now with the Chiefs; they were both high-round DB draft picks who starred under Foster in the same Hokies backfield in 2013 and 2014.

"My whole family loves [Foster] and loves all the Virginia Tech coaches," Fuller said. "He has always gone to [bat] for us, and that means a lot."

They've all gone through their professional ups and downs, and that includes Foster, but Kyle Fuller said that Foster never changed or treated their relationship any differently, even when the Bears corner was at one of the lower points of his career in 2016. It was that year that he missed the entirety of his season with a knee injury and was not so subtly called out by Bears defensive coordinator Vic Fangio for Fuller apparently not showing enough desire to return to the field down the stretch.

Fuller appeared to be the latest in a line of disappointing Bears first-round picks. Foster felt the need to touch base with his old protege once more as he was entering a critical juncture of his career before the 2017 season.

"He doesn't come from a good family," Foster told PFW recently, "he comes from a great family. [Kyle] and I have always kept in touch. We've been there for each other."

Fuller knew if he wanted to land a big contract — from the Bears or another NFL team — he had to turn in a big performance in 2017. More than anything, a year after missing every game, Fuller knew he needed to be available as much as anything else following a mixed-bag career to that point.

Foster got the sense talking to Fuller that he was serious about this quest and that more than anything, taking care of his body was paramount in finding that end.

"You have to learn how to take care of yourself during the offseasons," Fuller said. "That's one thing I didn't know much about coming in."

Some of it included a better diet. Some involved more pliability and different strength and fitness routines. It also involved Fuller doing a better job of preparing himself prior to training camp, to allow him to sustain a full season's worth of wear and tear.

"One thing he talked to me about was that he learned over time how to take care of his body better," Foster said. "How to practice. How to prepare for the long haul of the season. Working to be a professional.

"That’s his makeup this past year, I think, and that’s what he told me. We have a long season in college football with the bowl games and everything, but nothing like the NFL."

Fuller agrees and admits that this part of his routine took a little longer to develop and mature with experience. He resists getting into the details of those changes — "eating healthy, eating smart, nothing too crazy" — but says it played a big part in his finest season to date in 2017.

He only intercepted two passes and wasn't voted to the Pro Bowl, but Fuller's 24 passes defended tied for third-best in the NFL. After issuing him the transition tag and warding off the Green Bay Packers' attempts to sign Fuller this offseason, the Bears rewarded him with a four-year, $56 million contract. Now he's considered one of the lynchpins of the defense again.

Bears DB coach Ed Donatell has seen Fuller develop over the past three-plus seasons, running the gamut from disappointment to injured to flourishing in Fangio's system, and has been impressed with the metamorphosis. And Donatell hasn't seen any dropoff since Fuller signed his contract, indicating he's had "a real strong camp, better than he's ever been."

Donatell added: "[Fuller] wants to take last season and springboard off of that. He's challenged himself to take it to another level."

Foster also believes that Fuller's maturation prior to his age-25 season was a big reason for his breakout campaign and the arrow is pointing up for 2018 on a Bears defense that returns much of its depth from a relatively strong season overall.

"A little more self-confident," Foster said. "I think that’s part of growing up. He was that way here. Quiet at first but then becoming a leader. It took a few years. I think you’re seeing a little of the same transformation now.

"You get into the NFL, and veterans can be intimidating. But he’s been through it a little more now. He knows the drill and is more comfortable with himself."

Fuller agreed. He also believes that offseason rounds of golf with Fangio — they're both big fans of the sport — have helped them bond and him earn an additional layer of trust with his current defensive coordinator.

"We've definitely bounded out there, gotten to know each other," Fuller said of his golf outings with Fangio. "It's good. We're competitive out there."

Foster isn't much of a golfer, Fuller said. But he and Foster clearly have bonded in other ways. And the teacher has seen the student come full circle — something Foster always believed would happen.

"It’s been great to see him blossom into the guy I always thought he could be," Foster said. "From my perspective, I just have loved seeing that development."