Brian Wilson (69), John Elliott (65), Jeff Freeman (66) and Freeman's brother, Robin (65), share second place at 14-under-par 202. Lucas Glover and Jeff Gove are one stroke further back at minus-13.
Tolles began his round three shots behind the overnight leaders. He opened by sinking a 10-foot birdie putt on the first hole of the Cattail Course at Whirlwind Golf Club. He chipped in for birdie on the par-3 sixth to get to 10-under.
Around the turn, he drained back-to-back birdies from the 11th and came back with a birdie on No. 15 to get to minus-13.
Tolles ran home a 55-footer for birdie on the 16th and followed with a two-putt birdie at the par-5 17th to grab the lead.
'This week, I've kept it out of the rough for the most part,' said Tolles. 'After three days, I've only hit it in the thick stuff three times. Tomorrow is a big day for me. My main focus is to get my PGA Tour card back.'
The Freeman brothers came from out of nowhere, to get into contention. Robin ran off five straight birdies to open his round and then birdied the seventh for six birdies in the first seven holes.
On the back nine, Robin Freeman birdied the 10th, but stumbled to a bogey at the next. He came right back to sink consecutive birdies from the 12th. However he faltered to a double-bogey at the 14th. He capped his 7-under round of 65 with a birdie on the 17th.
'I got off to a good start,' said an understated Robin Freeman. 'But I literally could have birdied the first 10 holes. All in all, 10 birdies on 18 holes is pretty good.'
Jeff Freeman spread out four birdies over the opening nine holes. He sank back-to-back birdies from the 12th, but dropped a shot on No. 14. He answered that mistake with a birdie on the 15th.
Wilson, who shared the overnight lead with Johnson Wagner, parred his first six holes. He birdied the seventh before two more pars to close out his opening nine.
He birdied three of the first five holes on the back nine, but closed with a bogey at the last.
Elliott birdied the first and later sank three birdies in a four-hole stretch from the par-4 fifth. After an eagle on the 12th, Elliott dropped a shot on 13. He birdied the 15 and 18th for a share of second place.
Tjaart van der Walt carded a 4-under 68 to move into eighth place at 12-under-par 204. Scott Sterling posted a hole-in-one on the par-3 sixth en route to a 5-under 67. He shares ninth place with Andrew Tschudin, last week's winner Scott Gutschewski, Mark Hensby and Ryuji Imada at 11-under-par 205.