Pappas moved clear of Fiji's Vijay Singh, John Huston and Pat Perez in second place, while RoccoMediate, David Peoples and Dan Forsman shared fifth on 65.
Mickelson believes Woods' play-off victory over RoccoMediate round Torrey Pines for the most recent of his 14 majors is a warning that has been heeded by the rest of the field.
