The New York Giants are on the trail of a linebacker, per a report from Peter Schrager of FOX Sports.
Casillas, 27, is a five-year veteran. He split time last season between the Tampa Bay Buccaneers and New England Patriots. Casillas has 18 starts over those five seasons, and has played both outside linebacker spots.
If memory serves, the Giants also expressed interest in Casillas a year ago.
The Giants are parting ways with outside linebacker Jacquian Williams, and also could be losing backup Spencer Paysinger. They are committed to Jon Beason and Devon Kennard at linebacker, but could use depth and flexibility at the position. Casillas played only 284 snaps on defense in 2014.
The free agency signing period opens officially at 4 p.m. ET Tuesday.