Complex sentence: After his contract with Birmingham expired, O'Brien spent pre-season with League Two club Bradford City, he impressed during trials scoring on his debut in a pre-season friendly against Burnley, and on 4 August 2009 signed a three-month contract.
Split into simpler sentences: After his contract with Birmingham expired, O'Brien spent pre-season with League Two club Bradford City. He impressed during trials, scoring on his debut in a pre-season friendly against Burnley, and on 4 August 2009 signed a three-month contract.