"In most American sports, fans have learned to block out the countless corporate partnerships inked by their favorite teams. Only the most deranged of fans knows the identity of the Official Ambulance Provider of the New Orleans Saints, or choose a cell phone carrier based on who bought naming rights to their team’s arena. While our brains’ ability to develop an ad filter allows us to still enjoy a sporting event despite the endless parade of brand name shout-outs, it does have its limits. The jersey, in all other sports save the WNBA, is sacred ground, where the proposal of anything beyond a tasteful swoosh or three-stripe pattern on the lapel causes fans to freak out as though the McDonald’s arches were being painted on the ceiling of the Sistine Chapel.
But in MLS, the jersey sponsor isn’t just accepted, it’s expected."
Very good read from The Classical's Rob Mitchum. Bonus: some quotes from HTIOT's Tweed Thornton are in the article as well.