Vegas shot a 5-under-par 65 to tie Scott Langley for the lead after the second round Friday. They were at 9-under 131 on the Old White TPC course in West Virginia.
Twenty-three golfers were within three shots of the lead, including seven at 8 under.
Vegas doesn't have a top-10 finish this season, but he's looking to change that. He made five birdies during a bogey-free round Friday, including two of his final three holes.
''I feel like I'm playing great, I just haven't been able to put it all together,'' the Venezuelan said. ''But I'm staying patient and working really hard to make it happen, and it's coming together.''
Langley didn't have the same birdie explosion as he enjoyed in the first round, when he shot 62 to take the lead.
Starting his round on the back nine, Langley made back-to-back birdies on Nos. 6 and 7 and shot 69.
''Following up a round of 62 is never super easy,'' Langley said. ''I left a lot of putts within 6 inches of the hole, just right in the heart. I need to be a little more assertive (Saturday) on the greens.''
Langley and Vegas had a chance to make noise last week at the Travelers Championship. Langley was four strokes behind eventual winner Bubba Watson entering weekend play, while Vegas was six shots back.
Both faded in the final two rounds.
The top four finishers at The Greenbrier not previously eligible for the British Open will earn spots at St. Andrews, provided they are among the top 12 and ties.
''That's one of the goals for the week,'' Vegas said. ''So we're going to try to go get it.''
Tiger Woods made little progress after a solid first round but avoided missing consecutive cuts for the first time as a pro. Woods shot 69 Friday and was at 5 under, four shots back.
Woods had more trouble reaching fairways on Friday. He found the water to the right on the par-5 17th for the second straight day, hit his golf bag with his driver in disgust, then nearly holed his 97-yard fourth shot and made par.
He salvaged his under-par round with a short birdie putt on the par-3 18th. He declined interviews afterward.
Langley is looking to become the third person to become a first-time PGA Tour winner by winning The Greenbrier in the tournament's six-year history.
So, too, is David Hearn, who was among those in the group at 8 under. The Canadian is still looking for his first PGA Tour win in his 164th event. His best finish was second at the 2013 John Deere Classic.
''This would be a great place for me to win one, but I've got 36 holes of golf (left),'' Hearn said. ''I'm playing great right now and I look forward to the weekend.''
Hearn birdied six of his first eight holes and shot 64. He and Jonathan Byrd were tied for the lead on the back nine before late bogeys slowed their momentum. Byrd shot 69 and also was at 8 under.
Sixty-seven golfers made the cut at 2 under. Michael Putnam had an eagle and four birdies on the back nine to make the cut on the number.
Steve Stricker missed only his third cut since 2010.
Heavy rains stopped play for 18 minutes in the morning. Occasional thunderstorms are forecast through the weekend.