▁some ▁NFL ▁back ups ▁such ▁as ▁quarter back s ▁Ch uck ▁F us ina ▁and ▁Cl iff ▁St oud t , ▁G ▁Bud dy ▁Ay de lette , ▁and ▁W R ▁Jim ▁Smith ▁who ▁had ▁limited ▁success ▁in ▁the ▁NFL ▁became ▁major ▁stars ▁in ▁the ▁US FL . ▁ ▁However , ▁many ▁NFL ▁back ups ▁strugg led ▁or ▁did ▁not ▁make ▁it ▁in ▁the ▁US FL . ▁ ▁Additionally , ▁the ▁US FL ▁also ▁l ured ▁in ▁NFL ▁star ters , ▁including ▁a ▁hand ful ▁of ▁stars ▁in ▁the ▁pr imes ▁of ▁their ▁care ers , ▁including ▁the ▁ 1 9 8 0 ▁NFL ▁M VP , ▁Cleveland ▁Brow ns ' ▁quarter back ▁Brian ▁Si pe , ▁the ▁Buff alo ▁B ills ' ▁three - time ▁pro ▁bow l ▁running ▁back ▁Joe ▁C rib bs , ▁and ▁the ▁Kansas ▁City ▁Chief s ' ▁three - time ▁pro ▁bow l ▁safety ▁Gary ▁Bar bar o . ▁ ▁History ▁ ▁Background ▁ ▁For ▁many ▁dec ades ▁after ▁its ▁in ception , ▁American ▁football ▁was ▁widely ▁regarded ▁as ▁a ▁second - t ier ▁sport ▁behind ▁baseball ▁which ▁was ▁long - reg arded ▁as ▁America ' s ▁national ▁past ime . ▁As ▁a ▁result , ▁the ▁el ite ▁levels ▁of ▁American ▁football ▁lack ed ▁the ▁financial ▁where with al ▁to ▁consist ently ▁fin ance ▁their ▁own ▁facilities ▁and ▁instead ▁played ▁primarily ▁in ▁ball par ks ▁hast ily ▁re - pur posed ▁for ▁football . ▁However , ▁since ▁grid ir on ▁football ▁in ▁particular ▁is ▁responsible ▁for ▁excess