Only hours earlier, James and the Chargers agreed to terms on a multiyear contract extension.
A source told ESPN's Adam Schefter that the deal is for four years and worth $76.4 million, with an average annual value of $19.13 million, making him the highest-paid safety in NFL history.
"I'm feeling amazing," James said after practice, talking with reporters for the first time since reporting to training camp more than three weeks ago.
James said he never doubted a deal would get done.
"All along, we were just very close," Chargers coach Brandon Staley said about negotiations. "I think these contracts, when they're so big, it's just over little things. You just have to stay patient and positive with the process."
James spent 14 practices participating in walk-throughs and roaming the sidelines chatting up teammates, but never stepped onto the practice field during negotiations at the direction of his agent.
"Heck yeah, it was super hard," James said about his hold-in. "Everybody knows how much I love football and how much I want to be out here. It was just hard."
On Wednesday, in a joint practice with the Dallas Cowboys, James put on pads for the first time, but participated only in individual drills. He is expected to increase his football activity daily and participate in team drills next week.
"Finally," running back Austin Ekeler said when asked about the team's reaction to James' deal. "He's a great player. Every time he's on the field, it's a whole different defense. The way he plays, the way he runs the defense, just the attitude he brings."
Veteran wide receiver Keenan Allen has described James as the heartbeat of the defense, and the team. Staley echoed those comments, also calling James an "impact player" in a statement he made only a day before the deal was finalized.
"When I see him, I'm like, 'That's a defensive back,' because he can play anywhere," Staley said Tuesday. "He can play either safety spot, he can play corner. ... He can rush the quarterback and make an impact as a blitzer, he can make an impact in man-to-man coverage, and then he can make an impact in zone defense, whether he's playing low or high -- and he's our signal-caller and the heartbeat of our defense."
James took those comments to heart.
"That's a privilege to me for people to be able to think of you like that," James said. "I feel like that carries a lot of weight and just have to keep getting better and not be satisfied with it."
James, 26, is a key playmaker on a defense that has heightened expectations this season after a significant upgrade in personnel.
The Chargers acquired outside linebacker Khalil Mack in a trade with the Chicago Bears to form a pass-rushing duo with Pro Bowl edge rusher Joey Bosa, signed Pro Bowl cornerback J.C. Jackson to a five-year, $82.5 million contract in free agency and also added defensive linemen Sebastian Joseph-Day, Austin Johnson and Morgan Fox.
"We know that we have a Super Bowl-caliber roster," James said. "We know what we have in our team. We just try to come out, whether it's defense or offense, and compete every day to get each other better."
With James' extension, the Chargers ensure that they have several of the NFL's top defensive playmakers, including Mack, Bosa and Jackson, under contract for the foreseeable future.
The 17th overall pick in the 2018 draft, James was entering the fifth and final season of his rookie contract and was scheduled to earn slightly more than $9 million. He has 257 tackles, 5.5 sacks, five interceptions and three forced fumbles in his career.
James earned All-Pro and Pro Bowl recognition as a rookie before playing only five games in 2019 due to a foot injury. He also missed the entire 2020 season because of a knee injury.
In 15 games last season, James recorded 117 tackles (tied for No. 3 in the NFL among all defensive backs), intercepted two passes, forced three fumbles and had two sacks.
Following an appearance in his second Pro Bowl in February, James underwent surgery on the labrum in his left shoulder.
Staley said Wednesday that James "earned every cent" of his new deal, pointing to the adversity he endured early in his career.
"This wasn't like every other big contract that gets signed, because you know what he had to go through in order to make it to this point in his career," Staley said. "He overcame a lot to earn this contract."
Information from The Associated Press was used in this report.