Sung Kang moved to the top of the leaderboard after carding a second-round 10-under 61 at the AT&T Byron Nelson in Dallas as Padriag Harrington and Seamus Power both made the cut for the weekend.
In a blemish-free round, the South Korean hit five straight birdies through holes five to nine to match the Trinity Forest course record and take the lead at 16 under overall, four shots ahead of Matt Every.
A second successive 69 saw Padraig Harrington move in the right direction on the leaderboard, but still finds himself 12 shots adrift of leader Kang.
With the cut at two-under par, Seamus Power began the day knowing he needed to shoot a low score to stay involved for the weekend and duly delivered. A round of 67, which included six birdies, moved the Waterford native to three-under par.
American Every rebounded from his lone bogey at the 14th hole with a birdie at the last to card a 65 and share a tie of second place with compatriot Tyler Duncan, who shot a 66.
Duncan hit a single bogey on the par-four 13th - but accidentally struck his wife in the head with the wayward shot.
The 29-year-old, whose round also included six birdies, said he did not know about the incident until after the round, but told the PGA website: "I'm just happy she's not hurt."
Masters runner-up Brooks Koepka followed his opening 65 with a 66 to sit in fourth on 11 under overall, two shots ahead of Scotland's Martin Laird.
Laird, who started the day tied in 22nd, completed the second round without a single bogey to finish in a share of sixth place after 36 holes.
It was a disappointing day for overnight leader Denny McCarthy, however, who had to settle for a round of 77, making one birdie, a double bogey and five bogeys.
