Complex sentence: Coleman served as a line judge for the first six seasons before being promoted to referee at the start of the 1995 NFL season after Dale Hamer was forced to sit out the 1995 NFL season after undergoing open-heart surgery.
Split into simpler sentences: Coleman served as a line judge for the first six seasons before being promoted to referee at the start of the 1995 NFL season. Coleman was promoted when Dale Hamer was forced to sit out the 1995 NFL season after undergoing open-heart surgery.