In three NFL seasons, cornerback Trevor Williams has run the gamut of emotions.

A total of 32 cornerbacks were selected in the 2016 NFL Draft – Penn State's Williams wasn't one of them. The undrafted free agent channeled that disappointment into a roster spot – and eventually a role as an every day starter – with the Chargers.

Heightened expectations entering 2018 were derailed by a pair of injuries that contributed to in-season struggles and shaken confidence.

Adversity has swung back into optimism this offseason. The 25-year-old said he's back to full strength, both mentally and physically. His head coach and defensive coordinator have taken notice during organized team activities (OTAs).

"I have to tell you, Trevor looks outstanding," Anthony Lynn said. "His confidence is back. He's playing like it in practice. His change-of-direction is night and day."

In Week 2 of the 2017 season, Williams replaced an injured Jason Verrett in the starting lineup. He finished the year with 15 starts, 54 tackles, 13 passes defensed and two interceptions. Los Angeles completed its 9-7 season with the league's No. 3 pass defense.

Pro Football Focus graded Williams as the NFL's 10th-best cornerback of 2017. He was becoming one of the team's ascending players, but building off of his year two success came with early challenges.

An ankle injury early in training camp kept Williams out of all four preseason games. He started the first seven regular-season games of 2018, but didn't perform to the standard he set the year before.

A lingering knee injury landed Williams on injured reserve on Dec. 13, 2018.

"I watched my old tapes and I made a lot of mistakes this past season," Williams said. "But, [it was about] going over my craft again, just going back to the basics – watching tape and having that one-on-one with my position coach and D-coordinator, and just seeing how I can get better."

Gus Bradley noticed that there was "a heaviness" to Williams' approach in 2018. He commended his corner for pushing through the tough times that transpired last season.

"That's the difference, I think, is that mindset – to come back from adversity and to come back even stronger," Bradley said. "I think that's what just makes him so special. He's not a big talker. He's not going to tell everybody the story. He just goes out there and plays, which is why I think it makes it even more endearing."

Bradley said he noticed the difference in Williams during phase two of offseason workouts and was cautiously optimistic entering OTAs. What he's seen over the last two weeks hasn't disappointed.

"He's back to the guy that we all know, his spirit and everything," Bradley said.

The focus for Williams in 2019 is having more fun and playing looser. He explained that 52 other players are relying on him to do his job, and it's up to him to deliver.

Williams has already shown an early track record of persevering in the pros. This offseason serves as a clean slate; a chance to rebound in a league that's also a never-ending audition.

"I feel good," Williams said. "My confidence is back. Like I said, when I'm healthy I feel like I can max out my abilities and do what I need to do to help the guys be successful. I'm just happy to be back, happy to be flying around and just making plays."