Cam Newton is in his fifth season with the Panthers and his third with Mike Shula as his offensive coordinator. Andy Dalton in his fifth season with the Bengals and his second with Hue Jackson as his coordinator. Russell Wilson in his fourth season with the Seahawks and with Darrell Bevell as his coordinator.

All three are having their best seasons in the NFL, both statistically and based upon any objective evaluation of quarterback play, and all three have their teams poised to make the playoffs.

Sam Bradford is only 13 games - and, really, only 11 after missing two games to injury - into his first season playing in Chip Kelly's offense. Comparing quarterbacks can be dicey, but any fair assessment of the position encompasses years and not just games or even one year. And Bradford's trajectory of improvement this season suggests that he may deserve a larger sample of games.

Kelly certainly sees it that way.

"Name any quarterback playing at a really high level now and they've been playing in the system for years, not for months, and that's what Sam's case is," Kelly said Monday, a day after the Eagles topped the Bills, 23-20, to move to 6-7 and keep their playoff aspirations very much alive. "He's just been playing in our system for months. But I've said it and I'll continue to say it, I just see improvement from Sam on a weekly basis that gets you excited about him."

In his first seven games, Bradford's passer rating was 76.4, which ranked 34th out of 37 qualifying quarterbacks. Turnovers were uncharacteristically the problem. He had 11 of them. In his last four starts, Bradford's rating was an eighth-best 97.5. He had only one turnover. And the Eagles won three of four.

There are still three games - possibly more - for Kelly to further assess Bradford, but he doesn't have the luxury of time that the Panthers, Bengals and Seahawks had with quarterbacks they drafted. That was the deal when Kelly traded for the 28-year old in the last year of his rookie contract with the Rams.

But it appears as if Kelly already has made the decision to try and bring Bradford back beyond 2015.

"We've always wanted Sam here," Kelly said. "We wouldn't have traded for him if we thought he was going to be here for a year."

Kelly never gave Nick Foles such an endorsement. But he inherited Foles. Bradford is the only quarterback that Kelly has brought to the Eagles to be the unquestioned starter. This is his guy and he is apparently rolling with him.

Bradford could have other options, especially if the Eagles offer somewhere in the range of what was reportedly a low-ball bid before the season. Kelly has the option to use a one-year franchise tag, which is expected to be around $24.5 million, but it would benefit both sides to work out something longer.

And generally, if both sides have mutual interest, more often than not an agreement will be struck.

Kelly used Newton and Dalton as examples for his argument, but Wilson also applies. Newton's rating in his first four years was 85.4. His rating this year is 96.9. There is so much more to Newton's game that numbers tell only part of the story. But he is legitimately an MVP candidate.

Dalton had an 85.2 rating in his first four seasons before a dramatic increase to 106.2 this season. He suffered a broken thumb on Sunday and the Bengals' hopes for finally winning a playoff game with Dalton have been dealt a potential blow.

Wilson may be playing the best out of any quarterback over the last four games. He had a 98.6 rating in his first three years - along, of course, with two Super Bowl appearances - but is leading the NFL with a 110.0 mark this year.

Kelly can't be suggesting that Bradford will need another three or four years in his system to peak. Bradford does have four years of NFL experience already under his belt, after all. But it isn't an exact science.

"There's no timetable on it. I don't think anybody knows," said Kelly, who has two years left on his contract. "But I just know it's not an easy position to play and just name a quarterback who is playing well right now and look at how many years he has been in that system."

Aside from Newton, Dalton and Wilson, there are the Hall of Fame-bound regulars like Tom Brady, Aaron Rodgers, Drew Brees and Ben Roethlisberger. But the best comparison for Bradford and the Eagles may be Carson Palmer - or at least they hope.

The Cardinals quarterback, who will face the Eagles on Sunday, is in his 13th season but only his third in Arizona. Palmer struggled in his first season in coach Bruce Arian's system. He tossed 22 interceptions and had an 83.9 rating. He made a significant jump in Year 2 - a 95.6 rating - but played in only six games because of injury.

Palmer has been phenomenal in Year 3. He has a 107.2 rating. Palmer had shown more glimpses of greatness in his earlier years than Bradford ever had. So to suggest that Bradford will show the same progress as Palmer would be an overstatement.

But Kelly did get the Bradford-for-Foles trade right, even if including the second-round pick in the deal can be argued with. Bradford's increasing comfort in Kelly's offense is obvious. Imagine if he had more consistency from the offensive line and more capable downfield receivers?

There are, of course, exceptions to Kelly's rule. The Bills' Tyrod Taylor is thriving in his first season in Greg Roman's system. The Raiders' Derek Carr is excelling in his first year in Bill Musgrave's offense.

Bradford hasn't been as good as either. But he has improved. Is it enough to think he'll warrant mentioning with Palmer and company?

Kelly appears to believe so.