Striker Aaron O'Connor signed for Rushden & Diamonds from Mansfield Town in mid-June 2009.

Aaron started his career at Ilkeston Town, having spells at Scunthorpe and Nuneaton Borough before returning to Ilkeston. Aaron played for Gresley Rovers between 2004 and 2007, playing 127 games and scoring 80 goals during that time, also picking up the Player's Player of the Year, Manager's Player of the Year and Supporter's Player of the Year awards two years running.

In 2006, O'Connor nearly signed for Rushden & Diamonds, under Manager Paul Hart at the time. He played in pre-season friendlies, however he returned to Gresley, later moving to Grays Athletic, where he played under Justin Edinburgh. O'Connor signed for Mansfield in 2008, playing 39 games and scoring 8 goals.

Assistant Manager Michael Stone commented "Aaron is a quick, exciting player and we are really pleased to have him on board at the right stage of his career. He can play with his back to goal as well as work the channels and fits the mould of the players coming in to this squad right now that are prepared to work just as hard both when we have the ball and when we don't."

Manager Justin Edinburgh also commented "His record at a lower level certainly suggests that he's a natural goal-scorer if he gets the right service. I feel he also knows what I expect from him - particularly because, like Craig Farrell, he brings a phenomenal work-rate."

Aaron made his Diamonds debut on 8th August 2009 in the 2-0 defeat by Salisbury City at Nene Park, and scored his debut goal for the club two weeks later against Forest Green Rovers.