Canadian Adam Hadwin moved to the top of the leaderboard at the half-way mark of the Valspar Championship in Florida, but a second round of 74 saw Ireland's Seamus Power drop down the leaderboard
Power, after an opening round of 66 was very much in the mix, but a double bogey six at the last saw him finish on two under - eight shots behind Hadwin.
Graeme McDowell only just made the cut at even par after carding a 67.
Hadwin, a 30-year-old who has yet to win on the PGA Tour, signed for a seven-under 64, built around five consecutive birdies after the turn.
That took him to the summit after 36 holes, and one in front of overnight leader Jim Herman, who followed his opening round of 62 with a 71.
South African Tyrone van Aswegen shot 21 places up the standings with a 65.
Reigning Race to Dubai champion Henrik Stenson left himself well-placed in a pack of three on seven under overall, joining Americans Russell Henley and Dominic Bozzelli.
Ian Poulter remained in touch at three under but Luke Donald (two over) will not be around for the weekend.