World number one Rory McIlroy was heading for an early exit from the Honda Classic after struggling to a second round of 74 at PGA National.
In a round interrupted twice by bad weather, McIlroy carded five bogeys and just one birdie to finish seven over par.
That was four shots outside the projected cut and 13 shots behind clubhouse leader Patrick Reed, the American Ryder Cup star carding a second consecutive 67 to lie six under.
Reed enjoyed a one-shot lead over compatriot Jim Herman, who had yet to begin his second round, with England’s Luke Donald on four under after matching Reed’s 67 and Scotland’s Russell Knox another shot back following a 68.
McIlroy came into the event on the back of winning the Dubai Desert Classic but had to birdie his last two holes on Thursday to shoot a 73 and was soon going in the wrong direction on Friday.
Starting on the back nine, the four-time major winner bogeyed his opening hole after a wild drive and then recorded seven straight pars before another bogey on the par-five 18th.
The 25-year-old briefly raised hopes of a fightback when he birdied the par-three fifth, only to bogey three of the last four holes to seemingly seal his fate.
Meanwhile, Northern Ireland pair Gareth Maybin and Gareth Maybin both missed the cut at the Joburg Open in South Africa.
European Ryder Cup captain Clarke finished up one one-over-par with Maybin on one under – which was three shots shy of the cut mark.
South African Wallie Coetsee leads by a shot on 12 under.