Will the MLB ever have a salary cap?

Seriously it really pisses me off how certain unmentioned teams (owned by George Steinbrenner) are allowed to basically go shopping off of other teams rosters simply because they have the money. Most teams have to go through repetitive cycles of trading away current stars and grooming their farm talent so that one day those youngsters might be good enough to be traded away for more young players and the cycle repeats itself. But I digress. Just wondering if MLB will ever have a salary cap such as the one in the NFL which keeps teams rosters balanced and making it possible for teams located in smaller cities like say... Green Bay, Cincinnati, Buffalo... to not only exist in the league but also succeed. It would be nice to see a team outside of New York, LA, Philly, Boston, Chicago, etc. actually be able to compete in baseball.