Complex sentence: Sidelined by injuries for fifteen months, in his comeback fight Grant fought and lost to Jameel McCline in 2001, where he was knocked down in the first round and had to retire due to a broken ankle.
Split into simpler sentences: Sidelined by injuries for fifteen months, in his comeback fight Grant fought and lost to Jameel McCline in 2001. McCline knocked him down in the first round, and Grant had to retire due to a broken ankle.