Harris English claimed a one-stroke lead following the second round of the Mayakoba Golf Classic.
English used a seven-under-par 64 to move top of the leaderboard in Playa del Carmen, Mexico on Saturday.
The PGA Tour tournament has been pushed back after heavy rain led to Thursday's opening round being washed out.
English – seeking his third Tour victory and first since winning the 2013 Mayakoba Golf Classic when it was known as OHL Classic at Mayakoba – had a bogey-free day.
The 30-year-old holed seven birdies as he improved to 13 under at the halfway stage, ahead of fellow American Vaughn Taylor (66).
Brandon Todd's second-round 66 left him two shots off the pace, while Danny Lee (70), Adam Long (69) and Robby Shelton (66) are a stroke further back heading into the third round.
Meanwhile, Russell Henley missed the cut in bizarre circumstances at El Camaleon Golf Club, where he violated the PGA Tour's One Ball Rule.
Henley was penalised eight shots after using a different type of golf ball than the one he started the second round with.
The three-time Tour champion looked to have carded a two-under 69, until Henley realised he had inadvertently used a different ball during the round as he signed balls to give away.
"It was a small dash, a different way it was marked that would have been easy to overlook," said TOUR Rules Official Brad Fabel. "He came to us and said he didn't know how it had gotten in his bag."