Britain's Kyle Edmund will face Andy Murray or Aljaz Bedene in the Queen's Club quarter-finals after his second-round opponent Paul-Henri Mathieu withdrew with a wrist injury.
World number two Murray's match with Bedene at the Aegon Championships has been brought forward to 13:15 BST.
It means there will be an all-British clash in the Queen's quarter-finals for the first time in the Open era.
Murray last faced a compatriot in 2006, losing to Tim Henman in Bangkok.
Murray, 29, takes on Slovenia-born Bedene, who gained UK citizenship last year and, at 58th in the world, is the British number two.