"I was obviously not at my normal level. It's pretty much the Tour de France over for me," said the Australian, who reportedly felt unwell before the start.
Evans was unable to stay with the other Tour favourites in the penultimate of four climbs on the hard, 197.5-km ride in the Pyrenees and was helped by team mates Amael Moinard and Stephen Cummings.
While he made it back on the descent, he was dropped again in the final Peyresourde pass overlooking Bagneres de Luchon, losing four minutes 47 seconds to Wiggins, second-placed Briton Chris Froome and Italy's Vincenzo Nibali.
Evans now finds himself in seventh position, 8:06 adrift, an unbridgeable gap four days before the finish in Paris.
"You've got to be optimistic but you have to be realistic. This year, things haven't been coming together. The retirement present I wanted to give to George Hincapie this year is not the one I wished I did," he said.
Evans's BMC team mate Hincapie will retire at the end of his record 17th Tour de France on Sunday.