Can Cole Holcomb end Steelers long search for a linebacking centerpiece

PITTSBURGH — Gene Chizik still remembers the first time he noticed Cole Holcomb. Only a few months into his first stint as North Carolina defensive coordinator, Chizik was overseeing a rotation of linebackers during a spring scrimmage. When a helmet popped off a member of the second string, Chizik called for the next available man to hustle on the field. A scrawny redshirt freshman walk-on jumped in the mix. He made a tackle on the very first play. On the play after that, he made another one — this time for a loss. “Who is that kid?” former UNC linebackers…