Singh, who is seeking his ninth win of the season, carded a 69 to finish at 8-under-par 134 alongside Tommy Armour III and Rod Pampling.
Byrd is in no danger of losing his PGA Tour card having won the B.C. Open earlier in the year for his second career victory. The 26-year-old can work his way into next week's Tour Championship, however, with a strong showing this week.
Byrd was four shots off the pace to start the day on the Copperhead Course at Westin Innisbrook Resort and hit his approach to 10 feet for a birdie at the par-4 second. He left his second shot in a bunker at the par-4 third and played out to 6 feet. Byrd missed the par putt and dropped another shot with a bogey at the par-3 eighth.
At the par-4 ninth, Byrd landed his second shot within 2 feet of the hole for an easy birdie and got it very close again at the 10th to make it two in a row. Byrd then drained a 20-foot putt at the par-5 11th for his third consecutive birdies.
Byrd two-putted for a birdie at the par-5 14th and sank a 25-foot putt for a birdie at the par-3 15th. He added a birdie at the par-4 18th for his share of first.
'This course is not that easy,' said Byrd. 'I think guys like this golf course because it's challenging. It's an awesome golf course. You cannot fake it around this golf course and shoot good scores. Tiger might be able to, but most of us can't.'
Sluman set a new course record with a 62 in the first round, but struggled to get things going on Friday. He played the back side first and managed a lone birdie over his first nine holes only to give that shot back with a bogey at the par-4 sixth.
The 47-year-old recovered with a birdie at the par-4 seventh en route to a round of 70.
'I had numerous opportunities to make at least a half a dozen birdies, and today I just didn't make them,' said Sluman. 'I guess that's kind of the way it goes.'
Armour also started on the 10th and rocketed out of the gate with birdies on his first two holes. He tallied another birdie at the 15th and picked up a birdie at the 18th to make the turn at 5 under.
The 45-year-old hit his third shot to 4 feet for a birdie at the par-5 first and collected back-to-back birdies from the fifth to complete a sizzling 64.
Pampling, who currently occupies the 30th spot on the money list and needs to hold that position to earn a spot in the Tour Championship, managed six birdies on Friday for a bogey-free round of 65.
'Obviously anyone can just go out there and win this golf tournament and pass me,' said Pampling. 'All I can do is play my own game, and hopefully at the end of the week, if someone passes me, I might make enough money to pass someone else.'
Singh collected four birdies and two bogeys to finish two shots back after a 69.
'Towards the end I started hitting some decent shots, but these greens are pretty tough,' said Singh. 'I'm in good position, looking forward to playing well in the weekend if I can.'
Kirk Triplett, Jesper Parnevik, Vaughn Taylor and Kent Jones share sixth place at 7-under-par 135. Justin Rose and Carl Pettersson were one shot further back at 6-under-par 136.
Defending champion Retief Goosen struggled with a 73 on Friday, but survived the cut on the number at even-par 142. Among the notables who failed to qualify for the weekend were Phil Mickelson, Davis Love III, Jim Furyk and Stewart Cink.
'I don't know what to say,' said Mickelson. 'It's a tough course for me to play well on, mainly because I don't read the greens very well. But it's a wonderful event. I'm just sorry I didn't play better.'