The Bills announced the signing on Tuesday. A person familiar with the deal revealed the terms of the contract to The Associated Press. The person spoke on the condition of anonymity because the Bills do not disclose that information.
Darby was selected in the second round, 50th overall, out of Florida State. He was the ACC's defensive rookie of the year in 2012, and helped the Seminoles win the 2014 national championship.
Darby's signing means the Bills have all six of their rookie draft picks under contract.
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