Mark McNulty, Allen Doyle, Vicente Fernandez and Tom Watson share third place at 4-under-par 68. Local favorite Tom Kite is one stroke further back at minus-3. He was joined there by Bruce Lietzke, Graham Marsh, Isao Aoki, Bob Charles and D.A. Weibring.
Floyd got on the board at the fourth when he dropped a sand-wedge within 4 feet to set up his first birdie. He came right back by sinking a 12-foot birdie putt at the next at The Hills Country Club.
The two-time Seniors Players Championship winner reached the par-5 eighth with his second shot. Floyd then drained his 18-foot eagle putt to jump to minus-4.
Floyd reeled off nine straight pars including a nice save on the 17th. At the par-5 closing hole, Floyd two-putted for birdie from 35 feet out to grab a share of the lead.
'I only missed two greens and made good recoveries at Nos. 2 and 17,' said Floyd. 'When you can hit 16 of 18 greens you'll do well. I haven't had any problems with my back for three or four months. I still enjoy being inside the ropes.'
Torrance had a much different round than his co-leader. He opened with back-to-back birdies from the second, then the 50-year-old three-putted for bogey at the par-3 fifth.
He came back to birdie the eighth, but again stumbled to a bogey on No. 9. Torrance erased his final mistake by rolling in an 18-foot birdie at the 11th.
Torrance, who owns 31 worldwide wins, birdied the 13th to get to minus-3. He dropped his second shot within 3 feet for birdie at the 15th and capped his round with a two-putt birdie at the last for a share of first.
'I played beautifully today. This was my best round on the Champions Tour,' said Torrance, who led the European Ryder Cup team to victory in 2002. 'I hit the ball really well today. I'm not trying to impress anyone out here, just trying to do the best I can.'
Craig Stadler and Bobby Wadkins head a group of eight players at 2-under-par 70. Jerry Pate, Dave Stockton, Jose Maria Canizares, Ben Crenshaw, Bruce Fleisher, Morris Hatalsky and Howard Twitty are one stroke further back at minus-1.
Hale Irwin, the defending champion, struggled in the opening round of his title defense. He stumbled to a 3-over-par 75, where he is tied for 55th.