There is no longer any question that Nick Foles is Chip Kelly's quarterback this season. As Foles enters his third training camp with the Eagles, the coach said that Foles must work on the "intricacies" that can take a quarterback "from good to great."

The "good to great" ascension can be difficult - a best-selling business book is devoted to the concept - and Foles will attempt it as he follows his record-breaking 2013 with a season that could determine his future with the Eagles.

Even though Foles has become a household name in Philadelphia and has flirted with NFL stardom, he has started fewer games than all but three of the NFL's 32 projected starting quarterbacks this season. This will be the first time he enters training camp atop the depth chart. He still has considerable room for growth.

"I think the big thing that makes it easy is I've been around my teammates for a couple of years now, and the O-line," Foles said. "And I know they're going to do everything they can to pick up the protection."

The receivers, just like the running backs, he said, will do what they can to get the ball. "And that's where the sense of comfort comes," Foles said.

Kelly said there's not much of an advantage in having Foles take all the first-team snaps after splitting snaps last season. The lineup rotations change, so most players get enough work. And even though Foles did not win the job out of training camp last season, Kelly said he believed in the then-second-year quarterback's potential even when Foles was behind Michael Vick.

"He has the physical tools," Kelly said. "He's 6-6. I think he's almost 250 now. He can make all the throws. He's smart, he's intelligent, he's got a great work ethic."

Foles' opportunity never would have come last season had Vick not been injured twice. Kelly said that even though he believed in Foles, he could not have started Foles over Vick based on the training camp and preseason results.

"You kind of lose your team if you turn around and say, 'I'm going to name this guy because I think he's better than the other guy, even if this other guy played really, really well,' " Kelly said. "It's still a results-oriented business that you have to prove when you're on the field."

Foles does not need to prove that he is the starting quarterback this summer, but he still has much to prove. There are quarterbacks who became either Hall of Famers or journeymen at the crossroads Foles has reached.

"I'm not being sarcastic, but I think he can improve on everything and I think he'll be the first to tell you that," Kelly said. "I think all the great ones feel the same way - that there's every aspect of their game that they can constantly improve, and I think that's what makes Nick really special."