Complex sentence: He was under the impression that he was heir-apparent to Brickhouse upon the latter's retirement; indeed, he later said that he had been "guaranteed in blood" that he would replace Brickhouse on Cubs television broadcasts in 1982.
Split into simpler sentences: He was under the impression that he was heir-apparent to Brickhouse upon the latter's retirement. He later said that he had been "guaranteed in blood" that he would replace Brickhouse on Cubs television broadcasts in 1982.