"I spoke to Ike about it and it's just a difference in really a philosophy," Marrone said. "We appreciate what Ike has done in helping us try to reach our goal this year and we fell short."
Hilliard played 12 years in the NFL with the New York Giants and Tampa Bay Buccaneers. He served as wide receivers coach for the Washington Redskins last season before taking the same position in Buffalo.
Marrone said he will continue to evaluate his coaching staff, including special teams coordinator Danny Crossman, who has taken heat after the Bills allowed a pair of long kick returns to LeGarrette Blount in Sunday's 34-20 loss at New England.
"We knew going into the year it was going to be a difficult situation for [Crossman]," Marrone said. "Obviously Danny is disappointed -- we all are -- in the performance in some of those areas."