Detry had eight birdies and a bogey to reach 12 under on another day of perfect conditions at TPC Sawgrass on Friday.
Michael Kim shot a bogey-free 63 to reach 10 under and was tied with Alex Smalley, who shot 65.
Jordan Spieth put himself in the mix with eagles on 13 and 15, shooting 65 to reach nine under in his second tournament since offseason wrist surgery.
Three-time PGA Tour winner Tom Kim and Christiaan Bezuidenhout also were nine under, each shooting 66.
Argentine Emiliano Grillo set off the biggest roar - and the only beer shower - of the day, slam-dunking his tee shot on the rowdy par-3 16th for an ace.
Tournament officials had tried to curb drinks from flying out of the stands at the stadium hole since Sam Ryder and Carlos Ortiz set off beer showers with aces in 2022. The new measures did little good after Grillo's shot flew in the hole and swirled around the cup before dropping to send the suds flying.
Justin Thomas nearly matched Grillo, hitting his tee shot on No.16 to three feet in a 68 that moved him to eight under.
Top-ranked Scottie Scheffler shot a bogey-free 66 to reach seven under after a wild ride in the opening round of his second start since suffering a freak puncture wound on his hand while cooking Christmas dinner.
A two-time Belgian Olympian, Detry shot 66 in the first round at TPC Scottsdale and opened his second with three birdies on the front nine in his bid for a first PGA Tour win.
His birdie on No.9 kicked off a run of three straight and he added three more — he hit to 2 feet on 16 — around a bogey on the 490-yard par-4 14th.
Spieth tied for 69th at Pebble Beach last week and scrambled from some tough spots to shoot 68 in the opening round in the desert. He managed one birdie on the front nine in the second round, but sank eagle putts of five and 11 feet on TPC Scottsdale's two back-nine par-5s.
Spieth added a birdie on No.17 after hitting just right of the short par four.
Coming off a missed cut at Torrey Pines, Smalley opened with a 67 and followed it up with four birdies in a five-hole stretch in the second round starting on No.2. The 28-year-old American rolled in a six-foot eagle putt on the par-5 13th and birdied the difficult par-4 11th, but bogeyed the par-5 15th when he hit his second shot in the water.
Kim, winner of the 2018 John Deere Classic, missed the cut in two of his three tournament to start the season, but had his game dialled in at TPC Scottsdale. After opening with a 69, he charged up the leaderboard by closing with four straight birdies to shoot a six-under 30 on the back nine.
Australian Min Woo Lee improved on his opening 70 with a 66 to move to six under. He jumped 26 positions and is now tied 18th.
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