Date of birth
After a short stint at Queens Park Rangers as a youngster, O'Brien signed a three-year contract with then-Premier League side Portsmouth in 2008.
Spells at Barnet, Brentford and Dagenham & Redbridge followed, before a return to Pompey last season.
The 25-year old made three appearances for the club as they won promotion to League One, finishing the season as Champions.
Liam then joined the Sky Blues last summer, and made 11 appearanes during the 2017/18 season, with a highlight coming in the FA Cup Third Round as he helped City to beat Premier League side Stoke City at the Ricoh Arena.