The Premier League were an ardent supporter of remaining in the European Union, with chairman Richard Scudamore very publicly arguing against the prospect of Brexit earlier this week.
Scudamore was adamant that leaving the EU would be hugely detrimental economically and all 20 Premier League clubs - including Sunderland - shared that stance.
But after the British public gave Brexit the thumbs-up, the repercussions on English football are one of many seismic unknowns hanging over the country.
Here are four question marks facing Sunderland and the entire Premier League:
1. Will existing European players in the Premier League require work permits?
Currently there are very strict regulations in place for non-EU arrivals, who must have featured in a minimum amount of games for their country to qualify for a work permit.
But for those holding a European passport, they benefit from the free movement to play in the Premier League without facing such a red tape.
Can they carry on like that (as seems probable) or will that system end?
There are more than 400 European players currently plying their trade in the Premier League and Sunderland have several, who wouldn’t necessarily meet the work permit requirements if they were new signings.
The likes of Vito Mannone, Jan Kirchhoff, Fabio Borini and Younes Kaboul all failed to appear for their respective nations last season.
New agreements could be put in place to maintain freedom of movement, while it may take several years for Brexit to actually be activated, but it’s a grey area.
2. How much will Brexit affect new signings from the Continent?
Sunderland have benefited from some wonderful European imports over the years - the likes of Stefan Schwarz, Yann M’Vila and Tommy Sorensen. (In fairness they’ve also had some big duffs).
But will overseas players be more wary of moving to England now, considering the red tape involved?
More significantly, if only the elite internationals meet work permit requirements, then that could force up price tags by millions.
Those hidden gems on the Continent - such as Kirchhoff - could suddenly be out of reach.
3. What will the affect be on youth development?
This is likely to be the biggest impact stemming from Brexit, as Premier League clubs will have to wait until youngsters have turned 18 before attempting to sign them.
Currently - under EU regulations - they are able to bring in players at 16, which has seen clubs like Arsenal develop Cesc Fabregas and Hector Bellerin.
Sunderland haven’t been great proponents of developing overseas talent in-house, but they have begun to do so over recent years.
Swedish pair Joel Asoro and Oliver Krusnell have both been members of the Under-18s squad this season.
On the flip side of the coin, that could be a benefit to the English national team, with the Premier League’s heavyweights forced to develop local talent.
4. Could Brexit hit Premier League clubs in the pocket?
The global and domestic television rights to the Premier League currently top more than £8billion.
Like it or not, much of that appeal stems from the best players from all over the world battling in one helter-skelter competition.
If the Premier League became more of a British-based competition, would it necessarily have the same appeal?
Considering the huge reliance on television money from clubs such as Sunderland, that could hit them hard.
If the value of sterling remains low too, then overseas imports would immediately become more expensive too.