Some nights, when Sam Darnold has down time at his apartment around the corner from the Jets' training facility, he'll pick up his latest favorite book and dive in.

"The Dichotomy of Leadership" was written by two former Navy SEALs, Jocko Willink and Leif Babin. And while it isn't exactly light reading, its subtitle underscores Darnold's ultimate goal as the Jets' quarterback: "Balancing the Challenges of Extreme Ownership to Lead and Win."

Starting as an NFL rookie quarterback, as Darnold has this year, is a physically taxing experience. Darnold will miss his second straight game Sunday against the Patriots because of a strained right foot. He could return next week at the Titans.

This can also be mentally exhausting. It's a challenge for kids in Darnold's position - and at 21, he is still very much a kid - to not get overwhelmed and worn down, and to stay sharp and sane amid a rookie quarterback's inevitable turmoil. (Darnold, with an NFL-high 14 interceptions during a 3-7 season, has experienced plenty of that already.)

So when the day's film study and game planning are done, Darnold leans on a routine of focused reading, leisurely TV watching, dinners with teammates, and FaceTime chatting with his parents back in Southern California, in order to remain mentally balanced.

"It's not easy by any means," Darnold told NJ Advance Media this week. "If it was easy, everyone could do it."

Before the Jets drafted him third overall, Darnold really only ever knew Southern California. He grew up in San Clemente and played at USC, an hour north. Now, he lives alone in Florham Park, a bachelor with no serious girlfriend. (His relationship with his college girlfriend, still in California, fizzled, as post-college, long-distance romances do.) But solitude suits Darnold.

"I'm an independent person anyway, so I'm able to be on my own," he said. "I can be alone and be fine."

During the season, he rarely gets mid-week relaxation time. When he does, he sometimes heads to a nearby deli for a solo bite -- and to chat with the people who work there, since he's gotten to know them well. Or he'll watch an episode of "Game of Thrones." (He's still catching up.) Or he'll crack open one of those leadership books. (Among his other favorites: "Tools of Titans" and "Extreme Ownership.")

Though Darnold's parents have visited for a few games, he hasn't gone home to California this season. But he isn't homesick, so he just stayed in New Jersey during the Jets' recent bye week.

"I miss home for sure," he said. "I miss the people the most and just the place in general. It's a little weird. But I'm really getting used to this."

Darnold hadn't been to the New York area before his pre-draft visit to the Jets. He is embracing it now. During the bye week, he bounced around the Dumbo area of Brooklyn with some non-football USC friends. And Darnold recently attended a Rangers game with Jets wide receiver Jermaine Kearse and his wife.

Kearse, who sits next to Darnold in the locker room, knows how exhausting a rookie year can be - especially for Darnold, the NFL's only first-year quarterback this season to start from the get-go. From the grinding pre-draft process through now, Darnold has barely gotten a chance to come up for air.

"I think the rookie year is the hardest year, especially for Sam," Kearse told NJ Advance Media. "There's no break. For rookies, it's just a year-long process of non-stop work, so it can be mentally tiring."

Rookies often hit a wall in late November. But Darnold - as much as he enjoys his alone time - hopes to avoid that wall by relying on his near-and-far support system of family, friends, and teammates, whether he is video chatting on his phone or going out to dinner.

"That's kind of how I stay sane throughout this whole process," he said.

Said Kearse: "That's really valuable in this league because it's hard to get through things by yourself."

Darnold has gotten to know local restaurant managers well enough that he can call and get a private table for dinner with teammates. That group sometimes includes Darnold's mentor, 39-year-old quarterback Josh McCown, whose oldest child is less than a year younger than Darnold. McCown welcomes this quasi-fatherly role.

"I think the biggest compliment I can pay Sam is that he's always asking questions to gain knowledge and to help himself in the future," McCown said.

Ever curious, Darnold is stepping into this new chapter of his life - with all of its successes and failures - almost 3,000 miles from home. He plans to be here for a long time as the Jets' franchise quarterback, to overcome these early struggles, to live out that pointed line Willink and Babin's book:

"The foremost requirement for potent leadership is humility, so that leaders can fully understand and appreciate their own shortfalls."

These are the thoughts that stick with Darnold as he awaits the opportunity to bury memories of his most recent game - that four-interception mess on Nov. 4 in Miami - and build on the lessons of this uneven rookie season.

"Especially when I have a game like I did in Miami," he said, "I'm not going to come in here Monday and pretend to be: 'Everything is going to be OK, man. We're fine. Let's get after it.' It's OK to sulk a little bit, because losing sucks. But at the same time, I'm just trying to stay positive throughout the whole thing. That's really what I'm trying to be."

Darryl Slater may be reached at dslater@njadvancemedia.com. Follow him on Twitter @DarrylSlater. Find NJ.com Jets on Facebook.