During a two-minute drill against the first-team offense at Los Angeles Chargers minicamp earlier this month, James read Rivers and stepped in front of a pass intended for Keenan Allen for an interception in the end zone.
"My eyes were on the quarterback, and I just saw where he was looking," James said. "I dropped into my zone, and I was where I was supposed to be and made the play."
Those kind of instincts are a prime example of what Chargers defensive coaches expected when the team selected the Florida State product No. 17 overall in this year's draft.
Chargers defensive backs coach Ron Milus said everyone in the building was excited when it appeared that a top-10 prospect like James would still be available when the team was on the clock.
"Obviously he has the physical traits -- his size and speed," Milus said of James. "But I think the biggest thing that really sold me is that this is a man's man. He's a professional and you can sense that when you talk to him."
Chargers defensive coordinator Gus Bradley also remarked that while James is not one of the leaders of the defense as a rookie, he does have charismatic qualities that come through on the field.
"You're starting to see him more and more [assert himself]," Bradley said. "... [Now] you'll hear him talk like 'Hey, it's third down and this is what we need to do.' So you're starting to see him and hear him a little more as time goes on. I think as he gets a better feel for things those qualities will show even more."
While James performed with confidence and flashed playmaking ability during offseason work, Chargers defensive co-captain Melvin Ingram said the Florida State product has a long way to go before he develops into one of the top performers on defense.
"No, I wouldn't say as a leader," Ingram said. "He's out there doing what he's supposed to do and making plays, but you don't come in and do a three-day minicamp and some OTAs and become a leader. That's not how it works. You've got to put your time in the right way."
James is an alpha dog and has probably been the best player on his team since high school, but there's always an adjustment when it comes to playing in the NFL.
"For the most part, he's had an outstanding spring," Chargers head coach Anthony Lynn said. "We've put a lot on his plate. He's taken more reps of any DB on the team right now, and I think in the situations we've put him in he’s handled very well."
Helping James grow on and off the field has been a veteran defensive backs group led by Jahleel Addae, Casey Hayward and Adrian Phillips. In fact, he's already part of the family according to Hayward's Instagram account.
Addae is paying it forward. Veteran safety Eric Weddle did something similar for Addae when he signed as an undrafted rookie out of Central Michigan in 2013. Now Addae has taken James under his wing.
Addae serves as James' film study buddy in the meeting room and his sounding board when the Florida State product has questions on the field.
"He sits right behind me in the meeting room, and he's always helping me, always telling me ways I can get better," James said of Addae. "He's a great help.
"He doesn't have to do that. It's not like college, where you're supposed to look out [for people]. So for him to be able to do that, I respect him a lot for it."
Addae offered some simple advice to James: Be yourself.
"I told him just to play ball," Addae said. "There are a lot of expectations coming in as a first-rounder, but he has every tool in his toolbox to be a great safety.
"He can cover. He's rangy. He's fast, he's explosive, and he's smart. He's picking up the defense both at free and strong [safety], and he's making plays in the first few practices we've had. His future is bright."
James mostly worked with the second-team defense at strong safety in practices open to reporters during offseason work. But he also started at strong safety when the Chargers went to their dime package (six defensive backs) for obvious passing situations.
"We're trying to get him to see what he does well, what his skill set is like," Bradley said. "What I love about him, even though he might be burdened mentally, it doesn't slow his game speed down. He still plays fast."
The Chargers used at least five defensive backs on 434 snaps last season, according to ESPN Stats & Information, so James likely will work his way onto the field.
He looks forward to growing as a player on a talented defense that includes Ingram, Joey Bosa, Jason Verrett, Brandon Mebane, Denzel Perryman, Hayward and Addae. He has already made an impression on them.
"Watching him move around and the type of body he has, I think he’s a really rangy, long athlete," Bosa said. "And the way he covers ground is impressive to me."
But the rookie knows he has work to do. He has no plans to travel to exotic locales during the break before training camp, choosing to stay in town to acclimate to his new home in Southern California. He's training to be part of that skilled Chargers' defense.
"It's a great group," James said. "I just feel like it makes me step my game up to another level playing with guys like that. You know they're going to give it their all and make plays, so it makes it easier for me coming in here to do my job and contribute to the team."