Complex sentence: He predicted he would not see another Triple Crown winner in his lifetime due to fresh horses coming in at each stage of contest; including Tonalist, six of the last eight Belmont winners did not compete in the first two legs of the Triple Crown.
Split into simpler sentences: He predicted he would not see another Triple Crown winner in his lifetime due to fresh horses coming in at each stage of contest. Including Tonalist, six of the last eight Belmont winners did not compete the first two legs of the Triple Crown.