The shirts were designed for New York Yankees fans and read "Boston Massacre," with a blood-spattered design over the lettering. They had been shipped to stores well before the two explosions that left three dead and more than 200 wounded.
The shirts reference the Bronx Bombers' sweep of the Red Sox in 1978 and in the 2006 MLB Playoffs. The phrase was borrowed from the 1770 incident in Boston during which soldiers from Britain opened fire on civilians in the colonies, killing five and wounding six.
"[The shirts] are older baseball shirts that were predominantly being sold through our factory store outlets," said Brian Strong, a spokesman for Nike.
"In light of the tragedy in Boston we took immediate action last week to remove this product from distribution."
Social media may have helped push the shirts off shelves faster, thanks to a photo and tweet from Eric Stangel, executive producer of the Late Show with David Letterman.
Saw this @ Nike Outlet. Told them they shouldn't be selling it. They said "We've been taking them down. (Continued) twitter.com/EricStangel/st…— Eric Stangel (@EricStangel) April 20, 2013
Nike previously pulled an ad from South African sprinter Oscar Pistorius' website that said, "I am the bullet in the chamber," after the Olympian was charged with shooting his girlfriend to death on Valentine's Day.