The news comes as a surprise to the Bills after the 26-year-old Butler completed his fourth NFL season.
Butler majored in government studies at Virginia, and spent the 2008 offseason interning at Kemp Partners in Washington DC with former and late Bills quarterback and congressman Jack Kemp.
"My passion for education, country and community is something that I am ready to devote my full attention to," he said in a statement released by the team. "I believe the best way to pursue these spheres of interest is to step away from the game of football at this point in my life."
Butler started all but two of the 33 career games he played in after being drafted in the fifth round of the 2006 draft. He was limited to just two games in 2009 after sustaining a serious knee injury in Week 2 against Tampa Bay.