Complex sentence: Casares played several more unremarkable years for the Bears, then went on to play for the Washington Redskins in 1965, and in 1966 for the American Football League's Miami Dolphins.
Split into simpler sentences: Casares played several more unremarkable years for the Bears. He then went on to play for the Washington Redskins in 1965, and in 1966 for the American Football League's Miami Dolphins.