Khan's stunning victory in the BMW PGA Championship at Wentworth two weeks ago – he was 471st in the world at the time – did not earn him a place at Pebble Beach.
The following day he went to Walton Heath to try to qualify, but missed out in a six-man play-off for the last five spots.
Back in action today in the Wales Open at Celtic Manor, the 37-year-old from Essex is now waiting to hear from the United States Golf Association where he ranks amongst the stand-bys for the second major of the year in two weeks' time.
"I've got a tentative booking on a flight. If I'm first reserve I'll definitely go and if I'm second or third I'll have a decision to make, but I think I still would."
Khan has received "hundreds" of messages since his life-changing success. "By Wednesday last week it started to sink in – and then it hits you," said the man who last November lost his Tour card and had to make his tenth trip to the qualifying school.
"I'm still taking it in, but I want it to be part of the journey."