Back in the day when I lived in NJ and worked in Philly I had to pay Philly wage tax for the days I was in the office. So if I worked from home 1 day a week, I paid wage tax on 4 days worth of work. Payroll hated it but it added up. I also was able to use the wage tax I paid as a Federal tax deduction.
My assumption is the Phillies, Eagles, Flyers, Sixers etc pay wage tax on any time they are in Philly. So if the Phillies play a 10 game home stand they are paying 10 games worth of wage tax. Now I am not sure how that works with visitors but I would assume its the same thing.