Complex sentence: At the time of his retirement, he had the highest passer rating among NFL quarterbacks with at least 1,500 passing attempts (96.8), and as of October 2015, he is ranked fourth all-time and is the ranked highest amongst retired players.
Split into simpler sentences: At the time of his retirement, he had the highest passer rating among NFL quarterbacks with at least 1,500 passing attempts (96.8). As of October 2015, he is ranked fourth all-time, and is ranked highest amongst retired players.