Standing 6ft 10in, Jefferson was tipped as a future England batsman after scoring freely since making his Essex debut in 2002, and was named on the provisional National Academy intake for 2003-04, although not part of the final selection.
He scored over 800 runs in his first season for Essex, including 165 not out against Nottinghamshire in the final match to help wrap up the Championship Division Two title.
He averaged 52.25 during a hugely productive 2004 which yielded 1,411 championship runs, only to be dropped the following season due to dip in form.
He responded by posting the highest individual score for Essex in the Second XI Championship when he hit 266 not out against MCC Young Cricketers at Billericay.
Jefferson, who suffered a freak injury at the start of the 2006 season when he damaged tendons in his left wrist trying to open a hotel window during a pre-season tour to Cape Town, struggled to nail down a first team spot that summer, prompting a move to Nottinghamshire in 2007.
Early that year he impressed with the bat on England A’s tour of Bangladesh, but suffered a frustrating summer due to fitness problems and lack of form.
Released by Notts at the end of 2009 following two more seasons in which he failed to fulfil his potential, Jefferson joined Leicestershire for the 2010 campaign.
The highlight of the summer was a blistering 83 off 33 balls in the Friends Provident t20 win over Derbyshire at Chesterfield, and, despite an Achilles injury ending his first-team campaign in July, he had done enough to earn a new two-year contract.