San Francisco 49ers linebacker Chris Borland (50) is seen here in a game last year against the New York Giants. Borland, who had two interceptions in that game, has announced that he is retiring from the NFL after his rookie season. Chris Szagola/CSM/Landov hide caption

itoggle caption Chris Szagola/CSM/Landov

Baltimore Ravens linebacker Terrell Suggs waits on the field after the half the lights went out in the third quarter of Sunday's Super Bowl against the San Francisco 49ers in New Orleans. Mike Segar /Reuters /Landov hide caption

itoggle caption Mike Segar /Reuters /Landov

Head coach Jim Harbaugh (left) of the San Francisco 49ers and his brother, head coach John Harbaugh of the Baltimore Ravens, before a game on Thanksgiving Day 2011. Their teams will meet again in the Super Bowl. Rob Carr/Getty Images hide caption

itoggle caption Rob Carr/Getty Images