Vrabel has seen an expanded repertoire from Mercilus .
Texans linebackers coach Mike Vrabel sees continued growth from Mercilus one year removed from a career breakthrough year in which he registered a dozen sacks .
linebackers coach has seen an expanded repertoire from Mercilus .
Texans linebackers coach Mike Vrabel sees continued growth from Mercilus one year removed from a career breakthrough year in which he registered a dozen sacks .