Rains disrupted first-round action Thursday, there was another delay early Friday and there were still 61 players on the Annandale Golf Club course when darkness fell.
Summerhays, who has never won on the PGA Tour, is coming off a tie for fourth place at last week's John Deere Classic.
There were 24 players within three shots of the lead when the action was suspended and 12 of them are ranked outside the top 125 in money earnings on the PGA Tour this year. The leading 125 money winners at the end of the season earn full playing privileges on the tour next year.
Those a shot out of the lead included Chris Riley, Steven Bowditch, Jim Herman and Brad Fritsch.