Casey was one of only five players to complete the second round
Paul Casey shot a two-under-par 70 to take the clubhouse lead at eight under when fading light ended play in Friday's Houston Open second round.
The Englishman was one of only five players to complete two rounds after high winds suspended play on Thursday.
He is level with Australian pair Geoff Ogilvy and John Senden, who both failed to finish their second rounds.
Rory McIlroy is well placed on five under after 11, while Justin Rose is at three under following his 15 holes.
Ogilvy and Casey were two of the 72 players who had their first-round tee times pushed back to Friday.
Casey shot a six-under 66 in his first round, then raced the sun to finish a second-round 70.
Ogilvy and Casey are two of the 15 top-20 players at the Redstone Golf Club in Texas this week to prepare for the Masters later this month.
"I didn't think we'd get done, but we did," said Casey. "That was great."
After two-putting for par on 17, he ran to the 18th tee and hit a 318-yard drive into the fairway just before the round was officially suspended, allowing him to finish the hole on Friday.
"I figured it was worth it," Casey said. "There's something to be said about saving energy. It's turning into a long week. If I had to get up early (Saturday), that could have been very detrimental. I took a chance, ran for the tee."