The National Football League could play a full slate of eight regular-season home games across two London stadiums within the next five years, according to the league’s top executive on international endeavors. The NFL’s International Series has been a rousing success since it began in 2007, and while NFL officials have touted plans to expand the league’s British fan base, many experts are skeptical that a permanent London franchise would be financially viable.

League officials started to explore an expanded series of games in London after the 2014 season, which saw all three NFL games draw sellout crowds at Wembley Stadium, Mark Waller, the NFL’s executive vice president for international operations, told Sports Business Daily. Realizing that soccer-specific Wembley Stadium was ill-equipped to support more NFL games, the NFL reached a new deal with English Premier League club Tottenham Hotspur for shared use of its new stadium, which will open in 2018 and feature American football-specific facilities.

“Having two stadiums gives us significantly better options,” Waller said, according to SBD. “There will be a time in the next five years, if we wanted to, we could play a full season of games.” To play that full season of games, the NFL could merely expand its current system, which calls for teams to play one of their “home games” in London. Or, more radically, it could permanently relocate a franchise to London.

Establishing a permanent NFL franchise in London would be tricky, given how well things are going for the league’s 32 teams in their current markets. NFL teams split more than $7 billion in revenue for the 2014 fiscal year, with each franchise bringing in an equal $226.4 million. Tack on the team’s earnings through local revenue sources (the publicly-owned Green Bay Packers brought in $149.3 million in team-specific revenue last year), and it could be difficult to convince a franchise to move across the Atlantic Ocean to play in a market that is just starting to appreciate American football.

Experts told International Business Times last July that a permanent relocation would also represent a logistical nightmare, in terms of navigating Britain’s labor laws and facilitating in-season travel to and from America. The relocated franchise wouldn’t be able to cash in on stadium sponsorship or naming rights deals, either, since the team owner wouldn’t have a stake in the stadium. And while fans have turned out by the tens of thousands for the NFL’s limited three-game annual series, it’s unclear if an expanded schedule would routinely draw sellout crowds.

Britain’s interest in America football is growing, but Waller acknowledged any expansion to the league’s international series is contingent on building more support in and around the London area. The NFL will attempt to reach more television viewers through a new two-year deal with the BBC, and projects international subscriptions for its online streaming service to grow by up to 15 percent this season, SBD reported.

Shad Khan, the Jacksonville Jaguars’ owner, is among the staunchest advocates for the NFL’s International Series. The Jaguars have played an annual “home game” at Wembley Stadium since 2013, and will continue to do so through at least the 2016 season. Earlier this month, ESPN reported the Jaguars draw 15 percent of their team-specific revenue from their single yearly-game in London. Khan said the team is interested in a long-term deal to play in London through 2030.