Australian Rod Pampling is three shots adrift of leader Hunter Mahan at the halfway mark of the AT&T National on Friday.
Pampling fired off a four-under-par second round of 67, which included six birdies and two bogeys, to move to equal fifth and four under overall.
His countrymen Marc Leishman (two under) and Jason Day (one under) are tied for 11th and 15th spot respectively while Adam Scott (even) and Greg Chalmers (one over) have their work cut out for themselves.
Robert Allenby (seven over) and Nick O'Hern (17 over) missed the cut.
Mahan carded a superb six-under 65 to take a two-shot lead over the rest of the field at the Congressional Country Club.
The American produced the equal lowest round of the tournament so far to move into seven under.
In sweltering conditions, Mahan holed seven birdies and a bogey to be the best of just 18 players under par.
Zimbabwean Brendon de Jonge (69) and American pair Jimmy Walker (69) and Robert Garrigus (67) are tied for second at five under.
Tiger Woods, winner of the PGA Tour tournament in 2009, moved into contention with his three-under 68 taking him to two under at the halfway mark.
Mahan, whose only blemish came on the par-three second hole, said the hot conditions would play a big part in the final two rounds.
"Once your mind goes, the body is going to go with it. It's very important to be mentally strong," Mahan said.
"That's why guys work out all the time and try to keep our bodies in shape for days like this, when it's tough out there and it beats you down and stuff.
"We've got two more days of this, so it's going to be important to take care of yourself every night and every day when you're out on the golf course, or it's going to cost you shots."
Locked at four under are a group of five players, including Fijian Vijay Singh (70), Americans Pat Perez (69) and Stewart Cink (68), South Korean Noh Seung-Yul (68) and Pampling.
Overnight leader Bo Van Pelt could only manage a round of 73 to slip back to two under and a share of 11th with Woods, Charley Hoffman (68) and Leishman.
American Cameron Tringale (65) matched Mahan's round to sit outright 10th at three under.
South Korean KJ Choi was the biggest name to miss the six-over cut, while Michael Thompson, who finished tied for second at the US Open, will also play no part on the weekend.