Rubuta ci gaba don wannan sakin layi - A farkon kwanakin Major League Baseball (MLB), ba a ba da izinin maye gurbin ɗan wasa sai dai rashin lafiya ko rauni. Mai jefa kwallo marar amfani zai canza matsayi tare da wani mai kunnawa a filin wasa. Farkon bayyanar taimako a cikin manyan wasannin ya kasance a cikin 1876 tare da Boston Red Caps outfielder Jack Manning musayar matsayi tare da mai jefa Joe Borden. A wannan farkon zamanin, sauye-sauyen sauye-sauye daga matsayin matsayi zuwa akwatin kwalliyar a wannan hanyar ana kiran su sau da yawa "canji" kwalliya. Wannan dabarar sauya 'yan wasa tsakanin tudun da filin waje har yanzu ana amfani da shi a wasu lokuta a cikin wasan ƙwallon ƙafa na zamani, wani lokacin a cikin wasanni masu tsawo inda ƙungiyar ke ƙarancin' yan wasa. A cikin 1889, bayyanar bullpen ta farko ta faru bayan an canza dokoki don ba da damar sauya ɗan wasa a kowane lokaci. Masu ba da taimako na farko sun kasance masu farawa ne da ke ba da gudummawa guda ɗaya ko biyu tsakanin farawa. A shekara ta 1903, a lokacin wasa na biyu na gasar cin kofin duniya ta farko
, Bucky Veil na Pittsburgh ya zama dan wasa na farko a tarihin gasar cin kofin duniya.