The remains of Hurricane Gustav were expected to dump two inches of rain on the Bellerive Country Club course Wednesday night with more expected Thursday - when play is due to start.
But the field of 69 in the third of four season-ending playoff events might squeeze 36 holes into a day if needed at the $7 million tournament.
"It's quite a long course. If it rains, it's going to get even longer," Garcia (pictured with Singh) said.
Players were at this course in 2001 on September 11 when terrorists attacked New York and Washington, a stunning development that wiped out that event and one players recalled upon their return.
"Obviously you remember what happened because this is where we were at," Garcia said.
"It was a sad moment, but I think everybody got stronger from it. We moved on and I think that things are a little better now."
Singh has won the past two weeks to seize a huge lead in the chase for a $10m bonus for the points winner of the concluding series of events, even if he is not the man who takes the season-ending Tour Championship.
Singh has 120,500 points with Garcia next on 108,275 and Weir third on 106,965. Should Garcia win and Singh finish last, Singh's edge entering the final event on the last weekend of the month will be above 3,000 points.
"When Vijay won the first two it didn't help much, but it's definitely something extra to keep everybody involved," Garcia added. "We still have two more weeks, so hopefully we can finish it strong."
The bid to lure attention after the last of the major championships has met with mixed results. Last year several players skipped events and this year world number one Tiger Woods, the defending champion is injured and not playing.
That leaves the focus on Singh, who will pad his bank account, and those who hope for another victory or two against elite competition sandwiched around the Ryder Cup.
Singh will try to win a third event in a row for the third time in his career, having done so in 2004 when he won nine events. But his two nearest pursuers in points are also his playing partners this week.
"He is playing great golf and you can't do much about that," Weir said. "I'm looking forward to the pairing. I just want to get out there and try to get in contention again, try to win, and see where where that would land me."
Garcia, who won the Players Championship earlier this month, lost a playoff to Singh two weeks ago and shared fifth last week. He shared second at the PGA Championship.
Weir, second to Singh last week in Boston, seeks his first win of the year after losing for the ninth