The $1.7 million tournament begins Friday at Rock Barn Golf and Spa's Robert Trent Jones course and features five of the top 10 players in the standings.
Tops among them is Haas, who won the Greater Hickory Classic in 2005 and tied for second last year behind winner R.W. Eaks. He leads Langer by 98 points.
Also entered are Fred Funk, currently third in points; Scott Hoch (fifth), last year's tour No. 1 Loren Roberts (seventh) and Jeff Sluman, now eighth in points after winning at Pebble Beach, Calif., two weeks ago.
With Langer -- a two-time winner on the Champions Tour this year -- sitting out this weekend's tournament, he will slip further behind Haas, and could even fall to third in the standings behind Funk. Haas also could move atop the Champions Tour's money list. He trails Langer by less than $43,000, and would pass him with a top-10 finish.
Haas, however, isn't thinking about the points or money. He's more concerned with how he'll play in this weekend's tournament, as well as the remaining four events before the season-ending Charles Schwab Cup Championship in late October.
"There's a lot of guys still with a chance to gather in all the big prizes this year," said Haas, a two-time winner on the Champions Tour this year, including the Senior PGA Championship in May. "Fortunately, I'm one of those guys still in the mix. I have to play well. I have to worry about what I'm doing.
"I'd like to be a million dollars ahead on the money list and 1,000 points or more ahead, but I'm not. I need to play very, very well. I've been playing pretty well, so hopefully that'll continue," he said.
The National Weather Service has forecast showers and thunderstorms through Friday into early Saturday morning. The weather has affected play in this tournament nearly every year since it was first held in 2003, with showers forcing a suspension of play in three of the last four events.
"We'll just have to see how the weather holds out," said Eaks, who set a tournament record at 17-under par 199 in winning last year's Classic. "If it stays soft, you can just throw it at the pin. This course is harder to play when its harder, so it helps the drama of the tournament if the fans see more birdies."