One of the first things that new head coach Chip Kelly did was make it obvious that no one on the Philadelphia Eagles has his starting spot guaranteed, as he became notorious for using many players on the first-team offense during OTAs, and vice versa.
From the quarterback competition to the likely battles on the defensive line to the potentially revolving door at secondary, no one can enter camp completely assured of a starting spot.
Now a number of players will clearly enter the 2013 season as the starter. LeSean McCoy is the running back. DeSean Jackson and Jeremy Maclin are the top two receivers. Jason Peters is the left tackle. I could go on and on.
But a careful look at the roster reveals how many players from last year's team are not guaranteed a spot on the team. After all, that's what happens when a team goes 4-12 and ranks 30th in the National Football League in scoring differential.
The following slides will highlight a number of players who are right on the roster bubble right now.
Although the Eagles signed former Dallas Cowboys running back Felix Jones as a free agent this spring, the former first-round draft pick is not a lock to make the team.
The top two running backs are set in stone, with LeSean McCoy and Bryce Brown on top of the depth chart.
The competition for the third spot at running back will come down to Jones and Chris Polk, but Jones' past experience doesn't guarantee him a spot on the roster. Polk, who lost 15 pounds this offseason and has already impressed at OTAs, will give Jones all he can handle during training camp and the preseason.
Remember, past production will have no indication on Chip Kelly's Eagles team. That puts veteran slot receiver Jason Avant's job in jeopardy heading into the 2013 season.
Avant, now 30 years old, doesn't have the speed that Kelly looks for in his offensive skill-position players. He has tremendous hands, but he rarely makes plays after the catch, and he is one of the oldest players on the team.
His job as the team's slot receiver will be challenged by speedy Damaris Johnson, who caught 19 passes last year and is expected to be a breakout player in Kelly's 2013 offense.
If Kelly was forced to pick between Avant and Johnson for his team, Johnson would likely win. After all, Avant saw reps at defensive back. Johnson hasn't been forced to switch sides of the ball during minicamps.
Avant could still earn the team's fourth receiver spot, but he makes sense as a potential trade candidate to the Kansas City Chiefs, where he can be reunited with the head coach that drafted him back in 2006.
Clay Harbor's third year as the team's backup tight end was easily his best, as he caught 25 passes. But in just a few months, he's dropped from second on the depth chart to fourth, as the Eagles have drafted Stanford tight end Zach Ertz and added free-agent James Casey.
Like Avant, Harbor's likelihood of making the final roster took a big hit when Kelly began trying the tight end at outside linebacker.
Things could change during the next few months, but it could all come down to whether Kelly keeps four tight ends on his roster.
If he keeps three, Harbor is gone. If he keeps four, Harbor stays.
Danny Watkins likely has one final chance to prove that he is not a bust. The former first-round draft pick has been a major disappointment through his first two seasons, as he's been benched twice and has played in just 23 games in two years.
He's likely good enough to make the team as a backup guard, but if he suffers through a disappointing preseason and new head coach Chip Kelly wants to make a major statement with his team, it's possible that he cuts Watkins in the preseason.
After all, Watkins is going to be 29 this year, so age isn't on his side. What better way to show your new team who's in charge by cutting a player just two years removed from a first-round pick.
Antonio Dixon faces an uphill battle to make the Eagles' roster this season.
He's 28 years old and has played in just six games over the past two seasons. He's a defensive tackle who doesn't have experience playing at nose tackle and isn't suited for defensive end, which puts him out of luck in the Eagles' new 3-4 defense.
But he also is a big veteran body who has training camp and the preseason to show that he can make the successful transition to nose tackle.
A lot will depend on how comfortable the Eagles feel with veteran Isaac Sopoaga, as well as the progress of rookie Bennie Logan.
A fourth-round draft choice in 2011, Casey Matthews has not yet shown that he can be even an adequate linebacker in the National Football League.
He performed extremely poorly as the starting middle linebacker in 2011 before he was benched after just two games. He barely played in 2012, and his future with the team could come down to his performance over the next few months. (You also have to wonder if he has a slight edge in Chip Kelly's mind because he went to the University of Oregon.)
The Eagles will definitely have Brandon Graham, Trent Cole, Connor Barwin, Mychal Kendricks and DeMeco Ryans make the team at linebacker. The remaining spots will be fought for by Matthews, Jamar Chaney, Emmanuel Acho, Jason Phillips and Phillip Hunt.
Nate Allen and Kurt Coleman have been the starting safeties for the Eagles for the past three seasons. Both may not be on the team in 2013.
That's because the Eagles signed veterans Kenny Phillips and Patrick Chung. They also drafted Earl Wolff in the fifth round. Veteran special teams ace Colt Anderson figures to be in the running for a spot on the team as well.
Phillips' current knee issues could help out either Allen or Coleman, but it's hard to see both of them making the team. Even one might be a stretch. After all, they played brutally in 2012.