I don't see how this would help jersey sales. People are even less likely to wear skin-tight jerseys than they are to wear something sleeveless. Athletes can look good in a jersey like that because they're fit. No one wants to see Joe Blow in a shirt like that with his gut hanging out.
There's some truth in that, but a bigger size usually does the trick. I think people are thinking of this tight fit: But it's more like this, at least from the stomach area:
So stern allows this, but not our black jerseys?? Whatever dude!! Seriously though, I bet most players hate this! Or at least I would... I Can't play with sleeves