Baddeley carded a 70, Fasth a 71 and Ames a 69 that was the only round apart from Casey's under par.
Nick Dougherty of England, the overnight leader, settled for a 77 to join Woods on 145.
Defending champion Geoff Ogilvy of Australia posted a 75 for 146. Vijay Singh and Jose Maria Olazabal were among a group on 148 and South African Ernie Els, who won the last US Open held at Oakmont in 1994, was on 149.
The halfway cut fell at 10-over 150, which saw Mickelson miss it by a stroke after a 77.
He dropped six shots in four holes starting with a double-bogey at seven, followed by two bogeys and finishing up with another double-bogey at the 10th.
"That stretch really did me in," he said.
Other notable names who failed to advance included Scotland's Colin Montgomerie, who like Mickelson blew a chance to win at Winged Foot last year, two-time US Open champion Retief Goosen of South Africa and world No. 4 Adam Scott of Australia.
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