Lions head coach Jim Caldwell has watched his team undergo a drastic transformation -- in the wrong direction. Tim Fuller USA TODAY Sports

The Detroit Lions were a good team last year. They won 11 games and made the playoffs.

Now, Detroit is sitting at 1-7 halfway through the 2015 season. The Lions might be the worst team in the NFL right now, and they've given fans no reason to believe they'll turn things around any time soon.

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So, what happened?

Well, to start, you can point to the ground game on both sides of the ball. Last year's run-defense figures and this year's run-offense figures are nearly identical, as ESPN's Michael Rothstein pointed out on Twitter.

Last year, the Lions were able to stuff the run. Now, they're getting stuffed. While Ndamukong Suh and Detroit's formidable defensive front were the story of last season, this season has been about the offensive line's inability to open holes for Joique Bell, Ameer Abdullah and Theo Riddick.

The Lions currently rank last in the league when it comes to rushing yards per game (69.6); they rank second-to-last when it comes rushing yards allowed per game (133.8).

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