But before leaving, Rooney has left some suggestions for the American competition.
"The salary for a lot of players [is an issue here]," he told The Athletic. "I think, for the revenue the league is bringing in, the salary is not high enough for in particular the young American players.
"I feel that they're negotiating against other American players, they're not negotiating against what foreign players make, I don't think that's right for them.
"They deserve more, they're working the same as we're working, they're training as much as we're training, and I just feel that sometimes they get took advantage of."
Rooney also suggested the league should adopt a European-style transfer market.
"Players also get tied up," he continued. "I think players should be allowed to move from club to club [more freely] - a bit more like it is in Europe, where if one club wants to sign a player, you have to pay money, pay more on the salary.
"I feel here players can get moved on too easily, they can have a family, come home from training one day and they get told they're moving to the west coast, the east coast.
"For a family it's really difficult to just up and leave like that without any real notice. Free agency is absolutely a big one for players over here."
Need a VPN? Or seeking to switch? Then support Tribal Football by clicking here to sign up with our official partners NordVPN. Not only will you receive the best VPN experience, but also great discounts by signing up via Tribal Football. Thanks for your support!