Just days after NBA Clippers owner Donald Sterling received a lifetime ban, playoff hockey found itself embroiled in a racial controversy as well. Boston Bruins fans, upset after a 4-3 loss to Montreal in Thursday night's series opener, took to Twitter and Facebook—not to commiserate but to eviscerate.

Instead of the standard griping after a frustrating double-overtime loss, Boston fans began to lob incredibly hurtful racist tweets and messages at the Jamaican-Canadian PK Subban in particular. Several racial slurs were trending in the #BecauseItsTheCup hashtag when Subban scored, and most of the tweets are so offensive that republishing them seems barely ethical.

The Bruins organization, which signed the first black player in NHL history, Willie O'Ree, seems genuinely shocked by the behavior: "The racist, classless views expressed by an ignorant group of individuals following Thursday's game via digital media are in no way a reflection of anyone associated with the Bruins organization," Boston Bruins President Cam Neely wrote in a statement.

Mayor Marty Walsh responded simply  "This is a disgrace," adding "these racist comments are not reflective of Boston, and are not reflective of Bruins fans." Notably, many Boston fans have taken to the #PKSubban hashtag with messages of inclusivity in hockey, condemning racism as outside the spirit of the sport.

But no message of support can undo the troubling behavior. Unlike basketball, in which athletes of color seem to dominate the rosters, the NHL is markedly different. While there are certainly some notable players of color, (including Nazem Kadri, Ray Emery, Wayne Simmonds, Johnny Odyua, Manny Maholtra, and current Boston star Jarome Iginla) there is far less diversity on the ice. In light of this week's Sterling controversy, and of this winter's racially charged attacks on football's Richard Sherman, many fans are hoping to find a way to quash the escalating racism in American Professional Sports. Hockey is, after all, known for it's post-series handshake.

Boston faces off against Montreal for a nationally televised game this Saturday at 12:30 PM.