Complex sentence: He spent time on loan with Brentford in 2000 before helping secure Premier League promotion for Pompey in 2003 and was sold to Grimsby Town shortly afterwards where he spent two seasons before moving on to Northampton Town in 2005.
Split into simpler sentences: He spent time on loan with Brentford in 2000 before helping secure Premier League promotion for Pompey in 2003. He was sold to Grimsby Town shortly afterwards and he spent two seasons there before moving on to Northampton Town in 2005.