Three shots back at even-par 72 is Brian Forshaw, while Jake Harpe and K.P. Smith sit four shots back at 73.
Tinsley, who birdied No. 1 and gave it back and then some with bogeys at No. 2 and 5, made the first big move of the day with birdies at No. 8, 9 and 10 to go to 2-under. Tinsley then birdied No. 14 and 15 to get it to 4-under before giving one back on the way in at No. 17.
“There was a premium on hitting it in the fairway,” said Tinsley, who besides his championship run in 2009 has also finished runner-up twice in the tournament — the first in 2005 and the second in 2010 when he lost a sudden-death playoff on the fifth hole.
Brannon, who played in a group with Tinsley, agreed the rough was a factor.
“The rough was rough,” said Brannon. “I had to make some up and downs to start with. But once I got comfortable I hit some good shots.”
Once he got traction, birdies followed at No. 5 and 9. He gave one back at No. 11 before an eagle at No. 15 left him at 3-under. Brannon bogeyed No. 17 but redeemed himself with a birdie at No. 18 to finish the round tied or the lead.
“I was chasing Joey all day and finally caught him on the last hole,” said Brannon, who missed a 10-foot eagle putt at No. 5 and lipped out another chance for eagle on No. 9.
Forshaw, who opened the round with back-to-back bogeys, somehow climbed back into contention during a round that can best be described as a roller coaster ride. He birdied No. 5 and 8 and eagled No. 9 to get to 2-under, before he birdied No. 11 to go to 3-under. However, he gave it all back with a bogey at No. 12 and a double bogey at 13. He played even from there in, throwing up a birdie at No. 15 and bogeys at 16 and 17 before a birdie at No. 18.
If either Tinsley or Brannon win the title today they will become the tournament's first two-time winner since Chris Rivers won 2000 and 2003. Since then there have been eight consecutive first-time winners.
The leaders tee off 10 a.m., Sunday. Joining them in the final pairing is Forshaw.