Since 2007, when the NFL started its International Series, 20 franchises have made the journey to London for a regular-season game at least once. Three more first-timers -- the Indianapolis Colts, Washington Redskins and Cincinnati Bengals -- are among the six teams that will make the trip this year.
The difference between those games and what the NFL envisions for the future is that the teams playing in England have been returning immediately afterward to the United States.
Soon that could change.
Global expansion is one of the NFL's highest priorities. In addition to three regular-season games in London for the third consecutive year, the league will play a game in Mexico City in November between the Oakland Raiders and Houston Texans. Commissioner Roger Goodell is on record as saying he wants to take a regular-season game to China in the near feature, and maybe Germany and Brazil.
But nothing on the NFL's international agenda is as ambitious as its plans for London.
"The way I've always positioned it is it's our job to give the ownership the option to put the team there and create the right demand," said Mark Waller, the NFL's executive vice president of international. "And I would like to think that by 2020 that would be achievable if the ownership decided that that was something we wanted to do."
With it likely the NFL will push to have a franchise based in London within five years, here are 10 questions looking at why it would work, how it would work and why it might not.
Why is the NFL so sure London would support a franchise?
There have been 14 regular-season games in London. The average attendance for those games -- all at Wembley Stadium -- has been 83,061.
According to Waller, the NFL has 4 million "avid" fans in the U.K. and 14 million fans in total, with the majority living within a 2½-hour radius of London. According to the league, Sunday viewership of NFL games has more than doubled since 2007, and the Super Bowl audience has increased more than 75 percent.
"We feel very comfortable now the trajectory we're on will be able to create a fan base to fill a stadium," Waller said. "The best metric I can give you on that is all of the 80,000 tickets, more or less, that we see for Wembley, about half of those are sold to people who are buying all three of our games and have expressed a desire and intent that they would buy more if we were playing more games."
Where would the team play?
This was the other most pressing question for the league. For the first time this season, the league will hold a game at Twickenham Stadium, home of the English rugby team. Beginning in 2018, it will hold two games a year for three years at Premier League club Tottenham's new soccer stadium.
The NFL envisions a London-based team utilizing one or more of three stadiums, depending on scheduling conflicts. The 61,000-seat Tottenham stadium, set to open in 2018, will have a synthetic playing surface for NFL games underneath a retractable grass soccer field as well as dedicated locker room facilities for NFL teams. Unlike Wembley, Tottenham will not have to be reconfigured to host an NFL game.
"It may not be in one stadium, because obviously you're sharing in each case with someone else that already has a schedule of events," Waller said. "But we feel very good that we have the stadiums, and equally important we feel good about the ability to sell the same customer across stadiums. This year when we play Wembley and Twickenham, you as a fan could make a single transaction through Ticketmaster to buy seats and buy a season ticket if you like for all three games in a single transaction.
"So we put in place the ability to essentially have multiple venues for the same fan and the same ticket. That's a big breakthrough or step forward for us."
How would the NFL schedule games for a London team, given the travel implications?
This is still being discussed, but the working theory now is that the London team would alternate having chunks of games at home and then chunks of games on the road. So perhaps it opens the season with three games at home and then goes on a three-game road trip in the United States, followed by three more games at home.
Waller said the league also envisions the London team having a home base in the United States where it could practice and operate when needed.
What about the road teams playing in London?
Since 2007, the league has given each team playing in London a bye the following week. This likely would not happen when a team is based in London.
The issue for the road teams playing in London wouldn't be the distance traveled, one team executive said. It would the time zones traveled.
"One team is definitely going to be at a disadvantage from a time zone standpoint," the team executive said. "It's one thing when you get the week off after. What if you're Los Angeles or Seattle and you go to London as a road team? Good luck with that. That's an eight-hour time differential. That's just a mind screw. Maybe the schedule makers have it where a team coming out of a bye week from the West Coast is heading over there. So what do you do when you return? That's a tough one."
If the London team is sharing a stadium, what happens if it wins its division and hosts one or more playoff games?
The league hasn't figured this one out yet.
Said Waller: "The biggest issue we haven't yet -- I'll be honest -- really been able to find a solve for is the postseason, where you have from week to week a total unknown around whether you're in the postseason and if you are, are you home or away? And if you're away, where are you going to play. That's obviously an issue. It's an issue in the U.K. because obviously you're in someone else's stadium.
"It's possible to schedule ahead in lots of areas, but it's not possible to schedule ahead in the postseason."
How would a London-based team deal with the logistical issues associated with being an ocean away from the rest of the league?
The logistical headaches -- not to mention the accompanying expense for solving them -- would be massive. For instance, how would a London-based team deal with working out players? Say its star defensive end tore his ACL on a Sunday. Would it fly in free agents for workouts on a Tuesday, like other teams would? And what if a free agent didn't have a passport?
Would a general manager constantly fly back to the States to scout college players? What about scouts who advance upcoming games?
The league's answer to this, Waller said, is for the London team to have a base in the U.S.
"There's going to have to be a place in the U.S. that you are going to be headquartered from that's going to be the center of operations when you're on the road and for the management of your overall football squad and team and roster," Waller said.
Are the players going to agree to this?
Not without collective bargaining. The current collective bargaining agreement between the league and the NFL Players Association is set to expire after the 2020 season. While the NFLPA could do nothing about the Rams moving from St. Louis to Los Angeles, it would fight for concessions if the league puts a team in London.
"The big thing for us is we think it's a change in working conditions," said NFLPA president Eric Winston, an offensive lineman for the Cincinnati Bengals. "So obviously we would feel like that needs to be bargained out, exactly how that would work and what would go into it. I think the big thing for us is we've always been about growing the game, and growing the game has been good for players. It's been good for owners. And I think that will continue, but we don't want to give up health and safety to do that either. ...
"With working conditions, it's wages, it's hours, it's how you play, where you play. What's that doing on the body? That's what we're talking about. There are a lot of unknowns."
What's the biggest issue for the players?
The biggest issue, if it's not, should be the tax ramifications of playing in England. Those in the highest tax bracket in the United States pay 39.6 percent in federal taxes. Those in England pay 45 percent.
Plus, players on a London team would not want to give up their U.S. residency and thus would be subject to state and local taxes depending on where they live in the U.S.
How big of an issue are taxes? Take the Los Angeles Rams as an example. In addition to federal taxes, Rams players used to pay 6 percent in taxes to the state of Missouri and 1 percent to St. Louis. Now they must pay 13.3 percent to California, the highest state tax rate in the country. When the Rams play the Giants at Twickenham in Week 6 this season, the players will have to pay 45 percent in federal taxes to the U.K. -- while getting a partial foreign tax credit in the U.S. -- plus 13.3 percent to California and Medicare tax.
"The players will lose over 60 percent of their check for that week," said Robert Raiola, senior manager of the Sports & Entertainment Group of the CPA and advisory firm PKF O'Connor Davies. "I have no other way to say it: That stinks, and the players will say it worse than that. In short, they all agree that the situation is terrible.
"The players will never agree to (move to London) unless there's some sort of tax equalization clause, and I think it can be done."
Although he would not elaborate, Waller said the NFL is in discussions with England's treasury department on "taxation issues," adding, "We're making good progress there."
Would the league expand into London? If not, which team would relocate?
The NFL likely is not looking at expansion. It is happy with the 32-team model it has, with eight four-team divisions. So that leaves relocation.
Based on what we know now, the team most likely to relocate is Jacksonville. The Jaguars have played one regular-season "home" game in London for each of the past three seasons and are committed to doing so through 2020. Last year, 12.5 percent of Jacksonville's local revenue -- tickets, sponsorships and marketing -- came from playing in London.
Jaguars owner Shad Khan has pumped $76 million into Jacksonville's EverBank Field even though he doesn't own the stadium and another $11 million to redo the team's weight room, training room and locker room. Even so, what if attendance continues to be near the bottom of the league? And although the team appears to be on the uptick with coach Gus Bradley, what if it slips again?
What's the bottom line?
Having a team in London is a league priority, so the NFL will try to make it work. Those negatively affected will be collateral damage in pursuit of a greater goal.
"It's one of those things where I know all the problems," said the team executive. "But one of the things you learn in this league is it doesn't matter what the problems are, you better figure them out because if it's going to happen, it's going to happen, tough crap."