Open Extended ReactionsPITTSFORD, N.Y. -- Buffalo Bills running back James Cook came out to St. John Fisher University on Sunday afternoon but did not participate in a mandatory practice for the first time since seeking a contract extension this offseason. Cook, talking to a group of three reporters after practice, was asked why he did not participate. Cook was asked whether it was his choice not to practice Sunday, whether he was holding in and whether he planned to practice Monday. The Bills said "no comment" when asked about Cook, who is in the final year of his rookie deal, not participating in Sunday's practice. Cook is the Bills' lead running back but is part of a committee.