Ernie Els moved into contention for his third victory of the season after the delayed second round of the Valero Texas Open.
Friday's play was washed out due to heavy rain and a tornado warning and the tournament may need to carry over into Monday unless 36 holes can be played on Sunday.
Els, winner of back to back tournaments in the WGC-CA Championship and Arnold Palmer Invitational earlier this year, began the day six shots off the pace.
However, the South African carded a flawless 67 with five birdies and no bogeys to move up into a share of 12th place.
On a crowded leaderboard, that was only two shots off the lead shared by American duo Brett Wetterich and Jimmy Walker and Australian pair James Nitties and Matt Jones.
Jones, who carded a course-record 66 on Thursday, added a 71 on Saturday, while Nitties and Walker returned rounds of 67 and Wetterich a 68.
Seven players are just a shot off the lead on six-under, including American Pat Perez, who went one better than Els with a 66.
The lowest round of the day came from American Scott Piercy, who carded five birdies in a row from the first, and nine in total, in a 64 to join Els on five under.
England's Greg Owen is another player on five-under following a round of 68, a score matched by Sergio Garcia to lie three-under.