CARY, North Carolina (AP) - Tom Lehman knows a victory in the SAS Championship won't clinch the Charles Schwab Cup.

It sure would help.

Lehman, a three-time winner this year, has a 451-point lead over Mark Calcavecchia in the season-long race for the Champions Tour's Schwab Cup and its $1 million payout.

Both players will have to contend with one of the strongest fields to play the Prestonwood course in suburban Raleigh. Twenty players with at least one major victory on the U.S. PGA Tour are entered in the tournament that starts on Friday.

Russ Cochran won last year, beating 2009 winner Tom Pernice Jr. by two strokes.