ESPN's Adam Schefter has solved one of the NFC North's biggest mysteries: The duration of Detroit Lions coach Jim Schwartz's contract.

As you might remember, the Lions did not announce any terms of the contract extension Schwartz signed last June. According to Schefter, the deal runs through the 2015 season. That means the extension added three years to the four-year contract Schwartz originally signed in 2009.

There have been no indications that Schwartz's job was in jeopardy despite the Lions' performance this season. But according to Schefter, these terms guarantee Schwartz will return in 2013.

Schwartz and Green Bay Packers coach Mike McCarthy have the longest-running contracts in the NFC North. Minnesota Vikings coach Leslie Frazier is due for an extension but is currently signed through 2013. The same goes for Chicago Bears coach Lovie Smith.

Next up for our guy Schefter: Finding the Loch Ness monster.