Throughout those early days of 2013, when Chip Kelly was explaining himself in interview after interview as the NFL's hottest head coaching candidate, he revealed a dimension of his mind that remained rooted in conventional football thinking.

At Oregon, Kelly had unleashed that revved-up offense of his, and he had everyone wondering whether he believed that the speed and simplicity of his system would allow any quarterback to orchestrate it, that his innovations were enough to overcome any quarterback's shortcomings. But once Kelly got in front of those NFL executives and they prodded him for his philosophies, he made manifest his true beliefs about what it would take to succeed at football's highest level.

"He was very specific about feeling that in the NFL, it was extremely difficult to win without a really good quarterback," a person who sat in on some of Kelly's interviews said Tuesday, "and that if you didn't have one, you had to be looking for any opportunity you could find to even possibly get one."

To anyone who had been privy to those conversations, Kelly's decision to trade for Sam Bradford in March was hardly surprising. He had concluded that, after two 10-6 seasons and zero playoff victories, the Eagles had gone as far as either Nick Foles or Mark Sanchez could be expected to take them, and without a high-enough pick to acquire a quality prospect in the draft, Kelly had to get creative to give the Eagles a chance at finding a franchise quarterback.

The move was stunning because trades of such scope - this one involved two starting quarterbacks in Bradford and Foles, plus a second-round pick - aren't often made in the NFL. For its logic and forethought, though, the deal was reasonable. And if Bradford flourished in Kelly's system - if, after four so-so seasons and two ACL surgeries with the St. Louis Rams, he finally played like the No. 1 overall pick he had been - the trade had the potential to be brilliant.

So here are the Eagles now, three weeks into the regular season, and aside from the fevered comeback he led in that Week 1 loss in Atlanta, Bradford hasn't justified Kelly's leap of faith. The Eagles are 1-2, and Bradford has been skittish in the pocket, erratic with his passes, and reluctant to test opposing defenses with downfield throws. His performance has sparked a terrific chicken-or-egg debate: Has he played like this because of several mitigating factors, or has he played like this because this is how Sam Bradford plays?

Everyone has his or her own answer to that question. Yes, this is Bradford. Yes, this is Bradford, but the offensive line needs to be better. Yes, this is Bradford, but the wide receivers don't get open. No, this isn't Bradford, or, better yet, this won't be Bradford. He's rusty after sitting out almost two full seasons with that knee injury; he'll improve in time. He has too much talent not to.

That last factor seems the least excusable. Bradford is healthy and has been through three games. For all the rightful complaints about the Eagles' lousy run-blocking, Bradford hasn't been in jeopardy of absorbing a crushing hit since surviving Terrell Suggs' dirty dive at his knee during the preseason. If his injury-riddled past is preying on his mind whenever he sets up in the shotgun, he has to get over that fear, not just for the sake of the Eagles' season, but for the sake of his own NFL career.

"Part of being a pro is you have to deal with being hurt, and you certainly have to deal with injury," offensive coordinator Pat Shurmur said. "Coming back from injury is probably as individual as the individual. Sam's done a good job with his training. He's done a good job getting caught up as to how we function. As we go along here, he's just grinding through it like the rest of us."

The question that Kelly has to weigh, of course, is whether Bradford really will grind his way through these struggles. It is too early for Kelly to consider replacing Bradford with Sanchez, not after three games, and remember: By trading for Bradford, Kelly acknowledged that he didn't believe Sanchez was capable of leading the Eagles to a championship. But there's no getting around this: Sanchez can do what Bradford has done. Last season, he did more. He can complete short-to-intermediate routes. He can keep the offense rolling at the fast pace Kelly prefers. He can even run the zone-read from time to time. That doesn't make him a great quarterback, just better than the one Bradford has been so far.

So everyone watches Sam Bradford and waits, and maybe this Sunday's game against the Washington Redskins will mark the moment when everything turns for him, when he cleans up his footwork and stops short-hopping those 18-yard slants to Nelson Agholor and leading his receivers far too much on all his deep throws.

Maybe it all comes together for him, and everyone around the Eagles, starting with their head coach, will breathe easier if it does, because if Chip Kelly is being honest with himself, he has to be like the rest of us right now. He has to be wondering if he made the right move to get a franchise quarterback - and got the wrong guy.

msielski@phillynews.com

@MikeSielski