Complex sentence: In the mid- 1960s, Cubs manager Leo Durocher became frustrated with Banks, saying that the slugger's performance was faltering, and felt he was unable to remove Banks from the lineup due to the star's popularity among Cubs fans.
Split into simpler sentences: In the mid- 1960s, Cubs manager Leo Durocher became frustrated with Banks, saying the slugger's performance was faltering. Durocher said he was unable to remove Banks from the lineup due to the star's popularity among Cubs fans.