Two more American stars - 1992 Masters champion Fred Couples and 1996 US Open winner Steve Jones - have pulled out of next week's British Open at Carnoustie.
World number 19 Couples and Jones, who is 56th in the world, follow John Daly, Jack Nicklaus, Tom Kite, Ben Crenshaw and last year's US Amateur champion Hank Kuehne in withdrawing from the event's return to Carnoustie after 24 years.
Nick Faldo said he thought the American's pull-out was because of further back problems.
On the US Tour, John Maginnes fired a second round seven-under-par 64 to take the lead at halfway in the Greater Milwaukee Open yesterday.
He holds a one-stroke lead over Paraguay's Carlos Franco and Jerry Kelly after entering the clubhouse with 12-under 130 total.
Meanwhile, Ed Dougherty, whose physical ailments could fill a medical journal, fired a first round four-under-par 68 to lead the US Senior Open in Iowa on Thursday.
Gil Morgan, Bruce Summerhays and Walter Hall were two strokes back at 70. Christy O'Connor Jnr followed an opening 77 with a 73 yesterday to lie on six over par.
