KANSAS CITY, Mo. -- At home in Connecticut and about 1,200 miles from Kansas City, Chiefs offensive lineman Lucas Niang did his best to have his own rookie season while opting out in 2020 due to concerns about COVID-19.

He worked out four days a week, just like his teammates, he just didn't have a game on Sundays.

Niang spent 60 to 90 minutes working with trainer Brett Yarris of BX Movement in homework sessions of sorts, executing techniques the Chiefs wanted Niang to perfect during his season away.

Parts of some of their sessions are available on YouTube, including one centered on having Niang work on anchoring against a strong bull rush from an opposing defender.

Now Niang is back with the Chiefs as they begin offseason practices and he's hoping last season's work paid off. He could win a starting job at right tackle even after the Chiefs added six offensive linemen between free agency, the draft and a trade. Niang returns along with a 2019 starter, Laurent Duvernay-Tardif, who also opted out of last season.

"He put a lot of trust and faith in me and my process to lead him through his opt out year," Yarris said. "He made my job easy because he had retained so much of what the Chiefs wanted from him. It really just became about repetition and practice and work. He showed up every day. We didn't take vacations. We didn't take Christmas week off or anything like that. He showed up day in and day out ready to work so it was a joy.

"He's one of the most dedicated, hard-working guys that I've ever worked with. In fact, he's the gold standard. I've turned NFL clients away because they don't have his type of drive, his type of dedication."

Niang, the Chiefs' third-round draft pick in 2020, would have helped last season, particularly by season's end. At Super Bowl LV, the Chiefs were without four of their expected starting linemen because of injuries and Duvernay-Tardif's opt-out. They were overwhelmed by the defensive front of the Tampa Bay Buccaneers during a lopsided loss.

Niang wasn't initially planning to opt out last season but was concerned about reports of athletes struggling with myocarditis after acquiring COVID-19. He left training camp after only a couple of days.

"I just didn't feel comfortable, not knowing enough about the disease," Niang said. "It felt like the logical thing to do.

"I was thinking long term."

His long term began with the Chiefs' recent rookie camp, which he was allowed to participate in a year after being drafted out of TCU. The Chiefs didn't learn a lot but it was a start for Niang.

"I look forward to getting him back in the pads at training camp and moving around and doing what offensive linemen do, the real football part of it," coach Andy Reid said. "But until then, this gives him a chance to get acclimated mentally and physically as he goes forward. I think that's a good lead-up for him

"You can tell he's worked."

Some Chiefs fans on social media wondered about that after seeing video of Niang from rookie camp, thinking he was overweight and out of shape. Reid didn't seem concerned.

"He actually came in better shape than he came in last year, so that's a plus," Reid said. "You know he's been doing stuff, so he came in and looked like he got right back into it. For what we asked him to do, he was fine.

"Just getting him back into the swing of things, it looked like he did that well."

Yarris said he incorporated a functional conditioning period at the end of every training session with Niang. The idea was to mimic a two-minute drill. Niang would pass set, pass block, sprint 5 yards up the field and repeat the drill until they had covered 100 yards.

"I know his work ethic," Yarris said. "I know his character. I also know his weight so I know he's not overweight. I know he's in better shape after our work together than he was last year.

"He's right where he should be in terms of his weight and his physical conditioning. It's May. He hasn't played a game in 16 months. If he put pads on today because the Chiefs had a game, I'm sure there would be some challenges but I know he's right where the team wants him to be and expects him to be and he worked hard to get there."

A bigger challenge for Niang than being in shape is getting acclimated to real football after so much time away. He also missed the final five games of his senior season at TCU in 2019 because of a hip injury.

"I can only do so much to be an NFL pass-rusher," said Yarris, who at 6-foot and 240 pounds would be the pass-rusher opposing the 330-pound Niang during his workouts. "I'm not Frank Clark, Chris Jones or some of those other guys. The one thing we always spoke about in our sessions was to be as precise as possible because we need to take that precision and be prepared for the speed that was going to come in the NFL. That's the part that will take some adjustment for him like it does for any rookie. That's really what he is, a rookie."