Bradley Wiggins withdrew from the Tour de Suisse with a badly bruised right thigh on Wednesday, a day after crashing during the fourth stage.
The 2012 Tour de France champion, who also has a chest infection, will return to Britain for treatment.
Wiggins already expects to miss out on the Tour for a second straight year, with his Sky team to be led by defending champion Chris Froome.
Wiggins dropped time on the Tour de Suisse on Monday and was out of contention when he crashed 28 kilometers from the finish in Ossingen on Tuesday. He said he was trying to avoid an incident by staying at the back of the peloton.
''They all slammed on the brakes ahead of me but there was another rider riding full gas who rode straight into the back of me,'' he said in a statement.
He still finished the stage, 12 minutes behind the winner.
Wiggins said it made sense to him to quit the race, get healthy, and prepare for the British time trial championships in Monmouthshire on June 26.
