Gardner had been spotted by a Celtic scout while playing for the local college team in Manchester and impressed Celtic when he had a trial back October 2008.
He initially signed a one year deal at Celtic Park but that was extended to a three-year-deal in February 2009 but was released in the summer due to massive cut backs in the academy at Celtic.
Gardner arrived at Crewe in mid January after being recommended by Neil Baker and hw impressed quickly by netting the only winning goal in a trail game against Aston Villa.
Crewe manager Dario Gradi had said on record that Gardner had really impressed in training and did not look out of place.