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NFL free agency is always an exciting time for fans as they eagerly wait to see who their teams will sign. However, overpaying a player with boom-or-bust potential can sometimes blow up in an organization's face, as we've seen plenty of times over the past decade.

One of the biggest free-agent busts of all time, falling just outside this article's time frame, came when Washington offered defensive lineman Albert Haynesworth a $100 million deal in February 2009. Missed offseason workouts, a failed conditioning test and subpar play eventually led to the two sides parting ways and an aggressive cap hit to Washington's books.

While it's impossible to know how a player will pan out after he's signed, we can look back after the fact and evaluate how each one lived up to his contract. To define the worst deals of the decade, we'll have to measure expected play against actual performance, along with whether each player was able to finish his contract with the team that signed him.

With that in mind and this year's free-agency window approaching, let's take a look at the 10 worst contracts in the NFL since the start of 2010.