SACK FRANCISCO DEFENSE San Francisco 49ers Football Men's T-Shirt.
That's right, SACK FRANCISCO 49ers. The term was popularized when Justin Smith was seen in an interview in 2014 sporting a SACK FRANCISCO shirt, and it stuck! Or maybe it's the incredible defensive line of the San Francisco 49ers that has earned this name. Either way, Harbaugh and his 49er team are known for crushing the quarterback on defense.