It's possible for the Sabres but highly unlikely. As bad of an owner as Pegula has been the Sabres were still his "first love" before the Bills. If they go up for sale I can see a stipulation similar to Wilson (or even Golisano) that a buyer must commit to keeping the team in Buffalo. You have to remember that despite the dismal status of the Sabres, the franchise is worth 1.1 billion per Forbes. Pegula has made a very nice return on his original 160 million investment.
I'm not entirely convinced he is looking to sell. The arena upgrades are going to be the big determinant. I think Pegula is biding his time knowing NYS just invested so much in the Bills stadium and realizing his hockey club needs to become more competitive before asking for public funding.
Regardless, Buffalo is such a strong hockey market that it is very difficult to believe the NHL would want to see the team relocated whatever Pegula decides to do.