Complex sentence: Smith joined Oldham Athletic in May 2011 after the completion of his university studies, signing a two year contract and made his competitive debut on the first day of the 2011--12 season, starting the Football League match against Sheffield United.
Split into simpler sentences: Smith joined Oldham Athletic in May 2011 after the completion of his university studies, signing a two year contract. Smith made his competitive debut on the first day of the 2011--12 season, starting the Football League match against Sheffield United.