The league expanded by 4 teams 4 seasons ago in hopes of being able to avoid having to expand for a little while. It's definitely not outside the realm of possibility that the league still looks to expand soon as the teams have filled up again pretty quickly, but the ways the pros are structured, one conference is all North American teams and the other is all Europe so they'd add one to each presumably. Pittsburgh and Cleveland are definitely good options for the NA, although there are also places like Boston, Buffalo and Detroit to consider if it's not another Canadian team.