Roberts stands at 11-under-par 133. He was joined there by Brad Bryant and Don Pooley, who each shot 65 in round two.
Champions Tour rookie Rick Karbowski posted a 68 and stands alone in fourth place at minus-10. Danny Edwards carded the low round of the day as he shot an eight-under 64. He jumped into a tie for fifth place at 8-under-par 136, where he was joined by first-round leader R.W. Eaks (71) and two-time winner here, Hale Irwin (66).
Roberts tripped out of the gate with a bogey on the first, but that was his last mistake of the round. He birdied three straight holes from the second to move to 7 under at The Club at TwinEagles.
The 50-year-old picked up his next birdie on No. 10. Roberts dropped his third shot to the par-5 13th within 5 feet and he sank that for birdie and a one-stroke lead over Irwin and Bryant.
Roberts again moved one clear of Bryant with a 13-foot birdie putt on the 15th. Roberts sank a 10-footer for birdie on 17 to move two clear of the field. He parred the last though to end at 11 under.
'I played real solid,' Roberts said. 'I got a little wake up call on the first hole when I made bogey and then reeled off three birdies after that. I played real solid today after that first hole.'
Roberts is trying to make history this week as no player has ever won the first three events of the season on the Champions Tour. Five players have won three in a row, but none to start a season.
Bryant birdied his first three holes to get to 9 under. He dropped back to even-par for his round and minus-six overall after a double-bogey on the fifth and a bogey at the seventh.
The 51-year-old quickly recovered with birdies on eight and nine to turn at minus-8. Bryant two-putted for birdie on the 13th to join Roberts in the lead at 9 under.
Bryant got up and down for birdie at the 17th, then sank a 5-foot birdie putt on 18 to tie for the lead.
Pooley bogeyed the first, but got that stroke back with a birdie on No. 2. After another bogey on the fourth, Pooley parred his next eight holes.
The 54-year-old started to make his move with an eagle on the par-5 13th. He birdied the 15th to move to minus-8. Pooley ran home an eagle try on 17 to get within one, then converted a 14-foot birdie putt at the last to finish alongside Roberts and Bryant.
Dana Quigley, Peter Jacobsen and Keith Fergus each shot 3-under 69 on Saturday. They stand at 7-under-par 137 and were joined there by four-time runner-up Tom Watson (71) and Fuzzy Zoeller (70). Tom Kite and Gary Koch are one stroke further back at minus-6.