Vijay Singh, seeking his ninth victory of the year and within reach of the $10 million mark, was two shots out of the lead.
Byrd fired his second straight 5-under 66 to join Sluman at 10-under 132. Singh shot a 69 and was tied at 134 with Tommy Armour III and Rod Pampling.
Byrd had three straight birdies beginning at the ninth and finished off his round with a birdie at the par-4 18th.
Sluman set a course record with a 62 in the opening round, but had to settle for a 70 Friday.
"I had opportunities to make at least a half a dozen birdies and I just didn't make them," Sluman said. "I guess that's kind of the way it goes."
Among those missing the cut was Phil Mickelson.