As shared by the Twitter account of NBC's Sunday Night Football, it appears Green Bay Packers linebacker Clay Matthews took part in the filming of the opening video theme for the 2014 season on Thursday:

The @packers defensive star @ClayMatthews52 takes the stage #SNFOpen #SNF pic.twitter.com/fXfkEMZRfp

— SNF on NBC (@SNFonNBC) June 27, 2014

In past seasons, the musical accompaniment to the opening theme was sung by Faith Hill and Carrie Underwood.
#PACKERSmicroblog