It's a simple math equation: Chip Kelly says successful teams have strong quarterback play, and Sam Bradford is the worst-rated quarterback in the league.

Kelly, the Eagles coach, spoke before the team's practice Thursday, and the subject of quarterback play came up, NJ.com reported.

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On its surface, Kelly didn't say anything earth-shattering.

"You can say that every year this league has been in existence or the game of football has been in existence," the coach said. "It's the focal point of what you are doing ... your quarterback spot. That's the guy that has the ball on every play. How he distributes it, whether it's to the right guys or the wrong guys. Is he moving your team down the field, managing the game the way you want it managed? Very rarely is a team successful that doesn't have good quarterback play. There have been some exceptions, where it was a defense for the ages, and the offense was just kind of ... winning games 7-0, or 6-3. But most of the time the percentages are, if you get good quarterback play you'll probably have a good football team."

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Bradford, Kelly's quarterback, ranks last among the 32 starters in the NFL in Total Quarterback Rating with a measure of 29.6, and his passing efficiency rating of 76.4 places him at No. 30. No one would argue that Bradford has been a good quarterback in 2015.

There is one category in which Bradford ranks better than two of the NFL's more prestigious quarterbacks. Bradford's 10 interceptions places him at No. 29 in passing turnovers in the league. However, he is ahead of the Broncos' Peyton Manning, who is tied with Matthew Stafford at No. 30 with 11 interceptions, and the Colts' Andrew Luck, who ranks 32nd with 12 interceptions.

Perhaps, that is the reason Kelly has not publicly criticized his quarterback, despite the Eagles' 3-4 start to the 2015 season.

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