Day was 5 under through 14 holes when severe storms halted play Friday afternoon. When he returned to the course, Day promptly birdied No. 15 and added another birdie on the 18th to cap a 7-under 65. At 12 under, he holds a one-shot lead over Hudson Swafford, Daniel Berger and Chris Stroud - all in search of their first victory.
Day is making his first start in the Crescent City since 2009, but he is in the midst of a strong season highlighted by a win at the Farmers Insurance Open. He has five top-25 finishes in seven starts, with no finish worse than his T-31 at Trump National Doral.
Day ranks third on Tour in birdie average this season, with 4 1/2 circles per round, and his 15 birdies through 36 holes lead the field at TPC Louisiana.
With 12 players separated by only two shots at the halfway point, a weekend shootout appears likely on a course where 5-under 139 was required simply to make the cut. The group of players at 10 under, two shots behind Day, includes first-round co-leaders Boo Weekley and Brendon de Jonge, 2009 Zurich Classic winner Jerry Kelly and rookie sensation Justin Thomas.