Matt Kuchar was 10-under par on the 16th green when the second round of the Colonial was suspended Friday night because of an impending storm system.
There were 18 groups still on the course, three still with eight holes to play, when play was stopped at 6:38 p.m. The second round at Hogan's Alley will be completed Saturday morning.
Kuchar had a one-stroke lead over Graham DeLaet, the Canadian who shot a 67 in a morning round completed before an 2-hour, 10-minute delay just after noon because of lightning.
First-round leader Ryan Palmer was still at 8 under after shooting even par on his 12 holes Friday.
Jordan Spieth, Steve Flesch and Josh Teater finished at 8 under. Flesch had a 64, and Spieth and Teater shot 67.