The classy Serbian began 2009 as the world number one, but the 23-year-old has dropped down to sixth in the rankings following a disappointing start to the season.
A fourth-round defeat at the Australian Open saw Jankovic relinquish her No.1 status and since then she has endured a lull in confidence, exiting several tournaments in the early rounds.
Victory at the Andalucia Tennis Experience in Marbella threatened to ignite Jankovic's season, but defeat by unseeded Sorana Cirstea in the fourth round halted her charge at Roland Garros.
Her Wimbledon form also does little to suggest her maiden Grand Slam triumph will come on July 4.
She has never progressed to the quarter-final stage and lacks the versatility to pose a serious challenge on the grass.