Complex sentence: McMillan subsequently progressed through the ranks into the senior team, making his Premier Division debut during the 2008 season, coming on as a substitute in an away game against Cork City on 26 September.
Split into simpler sentences: McMillan subsequently progressed through the ranks into the senior team. He made his Premier Division debut during the 2008 season, coming on as a substitute in an away game against Cork City on 26 September.