It's possible (though maybe not likely) that they land a second compensatory pick for losing Ron Brooks, as well
One of the better sites for keep track of NFL salary cap data is OverTheCap.com, which also makes a valiant effort at trying to project compensatory picks for the following year's NFL Draft. They published their projection for the 2017 NFL Draft last week, and in it, the Buffalo Bills land an extra sixth-round pick for the free-agent defection of linebacker Nigel Bradham.
Two things to keep in mind regarding the projection: the possibility exists for the Bills to end up with another compensatory pick if things fall their way, which OTC accounts for in their write-up; and the projection includes three seventh-round picks, even though the NFL didn't put any compensatory picks in that round this past year.