FF Spin and Fantasy Football Crystal Ball kicked off its affiliation with USA Today by revealing Wednesday that Yahoo! led the way in its study of 2009 weekly player recommendations.

Yahoo! beat out a field of 10 fantasy sites to present the most accurate overall set of weekly position rankings, as measured by FF Spin and Fantasy Football Crystal Ball. Yahoo! took top honors for the season at wide receiver and team defense and reportedly edged KFFL for the overall prize. Fantasy Football Cafe, FF Today and FF Toolbox rounded out the top five.

“The overall winner was determined by a weighted average based on the cumulative results across all categories, a ’secret sauce’ of sorts,” FF Spin co-founder Scott Pashley wrote in the post on USA Today’s Fantasy Joe site. “Notably, two websites, FFToolbox.com and KFFL.com, actually outperformed the overall winner in one important category — top-five finishes by position. Each tallied five top-five finishes among the six categories tracked.”

JunkyardJake.com scored best at projecting quarterbacks, FF Today at running back and kicker, and FF Cafe with tight ends.

Throughout this season, the two “expert”-tracking outfits will be collaborating to present weekly grades at Fantasy Joe.