Couples, winless on the Champions Tour this season, finished 36 holes at the TPC-Harding Park course with a two-shot advantage over first-round leader Peter Senior. Couples did not suffer a bogey Friday as he reached 12-under 130 for the tournament.
This is the last event on the Champions Tour this year. The Charles Schwab Cup and the $1 million that goes with it will be awarded at the end of the tournament and the only players with a chance to win the year-long points race are Kenny Perry and Bernhard Langer.
The only way Langer can overtake Perry would be to win this tournament while Perry finishes outside the Top 5.
Bart Bryant was alone in third after 36 holes at 8-under 134. Langer was another stroke back -- five shots out of the lead.
Perry was in 11th place at 3-under 139. Also at that figure was defending champion Tom Lehman.
Martin Bashir resigns from MSNBC over Sarah Palin comments
Florida bear attack: Black bear mauls woman's face