They're at 18 under after a busy day in which much of the field had to complete the rain-delayed first round before starting the second. Merritt tied the course with a first-round 62 on Thursday.
"I just tried to keep pace today," Streb said after shooting 63 with nine birdies. "Obviously, the scores were very low, you get to place the ball and the greens are holding. Everybody's making a bunch of birdies and I'm just trying to keep up and have a chance tomorrow."
Sam Ryder and Blayne Barber each shot 63, and Billy Horschel had a 69 to stand within a stroke of the lead. Richy Werenski and Cameron Percy were two behind, J.T. Poston was 15 under, and four more -- including Hall of Famer Davis Love III -- were within reach at 14 under.
Information from The Associated Press was used in this report.