Complex sentence: He played 12 times for the "Reds" in the Premier League--13 overall--but his performances were not enough to secure a longer contract, and he was released by the club at the end of the season.
Split into simpler sentences: He played 12 times for the "Reds" in the Premier League, 13 overall. His performances were not enough to secure a longer contract, and he was released by the club at the end of the season.