PHOENIX - Chip Kelly has told us on more than one occasion that you judge quarterbacks by their win-loss record. Told us that again yesterday morning when he was answering yet another question about - who else? - Marcus Mariota, who won 36 of 41 starts and turned water into wine at the University of Oregon. OK, maybe I made up the water-into-wine part.

If that's true, if it's all about a quarterback's wins and losses, how do you explain the Eagles trading Nick Foles, who had won 14 of 18 starts the last two seasons, for Sam Bradford, who had an 18-30-1 record in five injury-plagued seasons with the Rams?

The answer is simple. Contrary to popular coaching opinion, wins and losses aren't the only measuring stick for quarterbacks. Sometimes a good quarterback is blessed with a terrific supporting cast and wins a lot of games.

That would be Foles.

And sometimes a better quarterback finds himself on a team with slow-footed receivers who couldn't outrun your Aunt Minnie, and has trouble breaking even.

That would be Bradford.

The Eagles' decision to swap Foles and a 2016 second-round pick for Bradford, who has missed 25 of the last 32 games with back-to-back ACL injuries, has everything to do with Kelly's good-to-great vision he shared with owner Jeff Lurie at the end of last season.

The Eagles put together back-to-back 10-6 seasons with Foles (and Mark Sanchez) at quarterback. But Kelly just wasn't convinced Foles could take them from good to great.

He thinks Bradford can if he can stay healthy. And, yes, that's a big if.

"When you're trying to go from good to great, you've got to take some gambles," Lurie said this week. "We have to be not risk-averse.

"It is so hard to find a franchise quarterback. It sets the ceiling on what you have as a team. You have to take risks when you can. They may not work. Or it may work. But that's what you have to do."

The Eagles have made a lot of dramatic personnel moves in the last few weeks. But the one with the biggest upside is the acquisition of Bradford, the former Heisman Trophy winner who was the first pick in the 2010 draft.

It's also the one with the greatest potential to blow up in Kelly's face if Bradford's twice-repaired left ACL betrays him again. But hey, no risk, no gain, right?

"Look at our starting receiver last year [Jeremy Maclin], who had 85 catches," Kelly said during his hourlong Q&A with the media at the NFL meetings. "Look at the year he had coming off of two ACLs.

"Look at our center. Jason Kelce had an ACL right before I got there and had a sports hernia in the middle of last season, and still made the Pro Bowl. Our left tackle [Jason Peters], who is arguably a Hall of Famer, has had two Achilles' [injuries] and is playing at an outstanding level.

"I would say it's easier for a quarterback with a knee injury [to come back] than a shoulder injury, as we went through the history of it. We didn't bring Sam in to run the ball 75 times a game. I think it's a lot easier for a quarterback with an ACL than it is for a receiver with an ACL. The history in terms of sports science right now and what doctors are doing is unbelievable."

Kelly was asked why he thinks Bradford is a better fit for the Eagles than Foles.

"When you look at Sam, it's his overall accuracy that impresses everybody when you watch him play," he said, even though Foles' career completion mark is 3 percentage points higher (61.6) than Bradford's (58.6).

So, Bradford is more accurate than Foles?

"I don't know about that," Kelly said. "But just looking at where we are and what we need to do, we've got guys open, and we need to put the ball on them in certain situations."

A lot of that has to do with getting the ball out fast, which Bradford can do.

Bottom line: When Kelly looks at Bradford, he sees a potential franchise quarterback. A guy who can take the Eagles to the Super Bowl and engineer a game-winning drive in the fourth quarter. For whatever reason, he didn't see that in Foles.

"In this sport, no matter what level you're playing at, you'd better have a really good quarterback, depending on what system you run," Kelly said. "I don't see many teams at any level that are successful that don't have a really good quarterback, whether it's high school, college or the pros."

Franchise quarterbacks don't grow on trees. There might or might not be two of them in this year's draft - Mariota and Florida State's Jameis Winston. But Kelly can't get his hands on either one without, as he says, mortgaging the future. And he says he's not willing to do that.

"Philosophically, I want to build through the draft," said Kelly, whose team has the 20th pick in the first round. "So if you gut yourself for 1 year and one guy, philosophically, I don't think that's the right thing to do."

Someone asked him whether he might make a play for Mariota if he slid on draft day and the Eagles didn't have to gut their draft to get him.

"I don't answer hypotheticals," he said. "What's it cost? Give me a hypothetical."

Two first-round picks, the questioner said.

"Where am I going? From where to where?" Kelly said.

Twenty to 6, the guy said.

"Never get you there. It took two first-round picks [for the Redskins] to go from 6 to 2, 3 years ago," he said.

Which brings us back to Bradford. Five years ago, he was the best player in the draft. Scouts considered him the best quarterback to come out of college since Peyton Manning in 1998. They considered him a franchise quarterback.

He played in an up-tempo spread offense at Oklahoma that is very similar to Kelly's.

He was plagued by injuries and a poor supporting cast much of his 5 years in St. Louis. No one ever questioned his talent. It was just a matter of whether he could stay healthy. Still is.

Kelly did his homework on Bradford. Reviewed tape of every one of his NFL passes. Talked to Bradford's college coaches.

"This [trade] was well-researched," Lurie said. "It wouldn't satisfy me if it wasn't."

Bradford still is rehabbing his ACL, which he tore for the second time last August in a preseason game against Cleveland. Kelly said he didn't know what Bradford's level of participation would be in spring OTAs.

"It sounds like he's on target to be fully recovered," Kelly said. "I just don't know what day he'll be cleared to go 100 percent. But I know he's running and moving around right now."

Can Bradford be a franchise quarterback? Can he be the Eagles' bridge from good to great?

"You hope so," the coach said. "But I'm not a predictor guy. I'm not going to put a label on anybody."

Email: pdomo@aol.com

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