Haven't heard of any instances where MLS teams refuse to let their players go on national team duty...but even if they have, it's not like it's just an MLS problem, it happens in other leagues as well. Regarding the FIFA calendar: while I would like to see them adjust and go along w/ FIFA, the problem is that you've got cities where it may be impossible to play Nov-Feb. Playing in the heat of the summer > playing in 5 degree weather and/or heavy snow in Chicago/NY/Colorado/Columbus. Makes it tough. There has been talk that they will indeed switch over to a schedule closer to FIFA's though. As dumb as some think the MLS heads are, I think they're doing much more right than they are wrong. This league is still in its infancy, relatively speaking.