Victoria Azarenka out of Wimbledon 2016
Injuries wrecked both 2014 and 2015 for the Belarussian, with a third consecutive year now threatening to go the same way for the two-time major winner.
Azarenka had three WTA Tour titles in the bag by early April as she enjoyed a stunning start to the year, yet a back injury hampered her clay-court preparations before she was forced to retire hurt in a first-round encounter with Karin Knapp at Roland Garros.
A Wimbledon statement confirmed: "Victoria Azarenka has withdrawn from the Ladies' Singles Championships 2016 due to a knee injury."
Azarenka's withdrawal could be followed by that of third seed Simona Halep, who has pulled out of warm-up events due to an Achilles problem.
The men's draw has already been hit with the high-profile withdrawal of Rafael Nadal due to a wrist injury.