Major League Baseball has banned "offensive" hazing in clubhouses, including having teammates dress as women, according to the Associated Press.
It has long been a tradition for teams to force rookies to dress in such outfits—often toward the end of the regular season after September call-ups.
The New York Mets provided an example at the end of this season with the entire set of rookies dressed as characters from "A League of Their Own":
Really nice of the rookies to get up early this morning and get coffee for the vets. #StillBetterThanAAA #Mets pic.