Complex sentence: Scheduled to run in December's Remsen Stakes at Aqueduct Racetrack, while in training the colt stepped on a stone and although only a very minor injury, his handlers chose not to race him again that year.
Split into simpler sentences: Scheduled to run in December's Remsen Stakes at Aqueduct Racetrack, while in training the colt stepped on a stone. Although the injury was very minor, his handlers chose not to race him again that year.