In the safety's first four seasons with the Eagles, he has been chief among his own critics, acknowledging that he's struggled at times. Allen recorded three interceptions as a rookie in 2010; in the three years since he has recorded the same amount.
But Allen earned the starting safety job this August by playing at a high level in the preseason, and he said this week he was never worried about his future in the league, or with the Eagles.
"Times get tough, and you just have to grow as a man and as a player," said Allen, who re-signed with the team on a one-year deal this offseason. "Like I said, I know the Lord has a plan for me. I just don't worry about those things. I know the Lord's watching over me, and if I just stay focused on what I need to do everything will fall into place. I don't worry about the things I can't handle and just worry about the things I can."
His coaches appreciate this mental toughness. Head coach Chip Kelly said Thursday that one thing Allen does especially well is avoid letting the stress affect him.
"Nate is not a guy that has bad days," Kelly explained. "Sometimes you see a guy walking down the hall and all of a sudden their shoulders will slump and something is bothering them or whatever. Nate is not that type of guy. He's come in here every single day with a mindset he's going to get better and I've seen that from him.
"He's striving to constantly improve and that's a real admirable quality to have."
Allen's improvement since Kelly took over has been obvious to the head coach. Last season, Allen recorded his first forced fumble and his first sack since his rookie season. He also picked up his first interception since 2011 and set a new career high in tackles with 94.
Kelly said he likes what he's seen from Allen this preseason, and thinks it's a sign of his still-young safety starting to take a very important step towards becoming comfortable in the Eagles' system.
"Better knowledge, better experience, and things have slowed down for him mentally," said Kelly of Allen, who is 26 years old. "You can see him starting to process things at a quicker rate. I think just because he's a lot more comfortable. He's a guy that was in a lot of different systems and had a lot of different coaches in the last couple years."
Since being selected in the 2010 NFL Draft, Allen has experienced four different defensive coordinators. This season, Allen heads into the regular season with a heightened level of comfort in the defensive system, which he says he appreciates.
"It definitely is a positive to be in a system two years in a row," Allen said with a smile. "Like I've been saying all Training Camp, instead of learning things and going through trial and error things, you're just reacting to things now. We're just fine tuning things."
Defensive coordinator Bill Davis echoed Kelly's sentiments about his starting safety. He's ecstatic to see Allen playing at this level right before the season starts.
"In my two years with him or year and a half now, (Allen) comes to work the same guy every day and he puts his head down and takes notes and he works," Davis said. "He practices hard and he's there every day with the same attitude, so I love to see him growing like he is and finally settling in and making plays."
Still, with his coaches excited to see what he will bring to the team this season, Allen is taking a measured approach to the safety job, remaining his own fiercest critic. He said he treats every day like he's fighting to keep his starting job, and so far, it's serving him well.
"That's the way this league is," Allen said. "Whenever you think you have something sealed up, that's when the bottom falls out. I go into every practice, every Training Camp thinking there's going to be competition, regardless."
Allen will enter Sunday's matchup with the Jaguars with the same mentality - one day at a time, and always playing with something to prove.