▁domestic ▁affili ate ▁is ▁the ▁Low ell ▁Sp inners ▁of ▁the ▁Class ▁A ▁Short ▁Season ▁New ▁York – P enn ▁League ▁which ▁is ▁approximately ▁ ▁away . ▁Boston ' s ▁fur th est ▁domestic ▁affili ate ▁is ▁the ▁G ulf ▁Coast ▁League ▁Red ▁So x ▁of ▁the ▁Ro ok ie ▁League ▁G ulf ▁Coast ▁League ▁some ▁ ▁away . ▁▁ 1 9 9 0 – present ▁The ▁current ▁structure ▁of ▁Minor ▁League ▁Baseball ▁has ▁been ▁in ▁effect ▁since ▁the ▁ 1 9 9 0 ▁season ▁when ▁the ▁Class ▁A ▁level ▁was ▁sub div ided ▁for ▁a ▁second ▁time ▁with ▁the ▁creation ▁of ▁Class ▁A - Ad vanced . ▁The ▁Ro ok ie ▁level ▁consists ▁of ▁domestic ▁and ▁foreign ▁circ uits . ▁▁ 1 9 6 3 – 1 9 8 9 ▁The ▁foundation ▁of ▁the ▁min ors ' ▁current ▁structure ▁was ▁the ▁result ▁of ▁a ▁re organ ization ▁initi ated ▁by ▁Major ▁League ▁Baseball ▁( ML B ) ▁before ▁the ▁ 1 9 6 3 ▁season . ▁The ▁reduction ▁from ▁six ▁classes ▁to ▁four ▁( Tri ple - A , ▁Double - AA , ▁Class ▁A , ▁and ▁Ro ok ie ) ▁was ▁a ▁response ▁to ▁the ▁general ▁decl ine ▁of ▁the ▁min ors ▁throughout ▁the ▁ 1 9 5 0 s ▁and ▁early - 1 9 6 0 s ▁when ▁le agues ▁and ▁teams ▁fol ded ▁due ▁to ▁shr inking ▁attend ance ▁caused ▁by ▁baseball ▁fans ' ▁preference ▁for ▁stay ing ▁at ▁home ▁to ▁watch ▁ML B ▁games ▁on ▁television . ▁The