While Sheehan was shooting 3-under-par 69 to move to 9-under 135 for two rounds, Todd made tour history by making a hole-in-one at the same hole (No. 17) at Jennings Mill Country Club for the second consecutive day.
"It's still hard to believe," said Todd, who shot 71 and is four behind Sheehan.
Aiken's Kevin Kisner, a co- leader after the first round, had 75 and is six shots back.
The three former Augusta State players in the field missed the cut, which fell at 144. Major Manning shot 71-74--145; Richard Johnson had 76-72--148; and Keith Guest shot 76-73--149.
CHAMPIONS TOUR: In Lutz, Fla., Larry Nelson shot 6-under-par 65 to take a one-shot lead over Nick Price after the first round of the Outback Pro-Am.
Mark McNulty and Mike McCullough had 67s, while Jay Haas shot 68.
Haas tied for second with Scott Hoch in this event in 2008.
The last time the 61-year-old Nelson held first place outright was at the SAS Championship in September 2001. His last 65 was more than two years ago.
Two-time defending champion Tom Watson, who had hip surgery Oct. 2, had 71 with two bogeys and two birdies.
EUROPEAN TOUR: In Beijing, Choi Ho-sungshot 4-under-par 68 to take a two-stroke lead after the second round of the China Open.
Choi is at 6-under 138 through two rounds.
Markus Brier (73 on Friday) and Chapchai Nirat (71) are tied for second place.