They're so upset, they've actually filed a lawsuit against the United States Citizen and Immigration Services department. 

The Athletic's John Vogl reports that the team was denied a claim to have their strength and conditioning coach working here who's a native of the United Kingdom. 

"U.S. Citizenship and Immigration Services has denied an immigrant alien worker petition for Edward Anthony Gannon, a native of the United Kingdom who was hired as the team’s strength and conditioning coach in 2015. On Tuesday, Gannon and the Sabres’ owners (formally known as Hockey Western New York, LLC) filed a suit in U.S. District Court against federal immigration officials for wrongly denying the application.

The lawsuit says the denial interferes with the owners’ ability to “successfully conduct its operations in the U.S. and potentially subject them to substantial financial harm and disruption in developing their athletes if Dr. Gannon needs to depart the U.S.”

Gannon has been with the team since 2015 and Kim Pegula says they followed all procedures to make sure they hired the best candidate and filled out paperwork. 

“Let me stress that we selected Ed after an exhaustive search across the world of professional sports performance,” Kim Pegula wrote on Gannon’s behalf.

“We spanned the globe to find an elite Strength and Conditioning expert because this role is absolutely critical to our overall organizational success. It is a critical role that is fundamental to our organization’s success both on and off the ice.”

“We spend tens of millions of dollars each year on world class athletes. We require our Head of Strength and Conditioning to expertly monitor and train these athletes so they achieve success on the ice. It is a critical role that we entrust to someone who also has world-class credentials and who can properly take care of our valuable assets.”

However the government simply isn't buying the Pegula's story and the evidence to prove he was a top tier candidate wasn't sufficient. 

“An individual with sustained national or international acclaim should be able to produce unsolicited materials reflecting that acclaim,” the immigration department wrote in its denial. “For instance, you did not submit national or international media describing the beneficiary’s significant original contributions.”

Source: The Athletic