Team principal Dave Brailsford is understood to have decided on eight members of the team, while Henderson appears to be one of three contenders for the last spot.
The others are Michael Barry (Canada) and Sylvain Calzati (France).
Chris Henderson said yesterday his brother was "waiting with bated breath" for the team announcement either tomorrow or Saturday.
"I spoke to Greg last night and he doesn't know if he is in or out.
"If he makes it he will be the last cyclist selected."
Henderson helped his chances when he won a stage on the Giro d'Italia.
"There were strong crosswinds and Greg went to the front of the bunch and won the sprint," his brother said.
"He is used to these types of winds from the Tour of Southland."
Team Sky is being built around star British rider Bradley Wiggins, who finished fourth on the tour last year.
Henderson proved he has the tactical skills when he won the points race at the Commonwealth Games and the points race at the world championships.
The early part of Henderson's cycling career was dedicated to the track, but he is now employed on the road.
He had his best season on the road last year, with a stage win at Vuelta a Espana.
Earlier this month, Wiggins went on a reconnaissance of some of the Tour de France's key stages with two team-mates, Barry and Steve Cummings (Britain).
Barry is strong on the hills and may be brought into the team to help Wiggins through the mountain regions in the Alps and the Pyrenees.
If Henderson misses out, the Sky team is expected to use Boasson Hagen (Norway) as its sprinter.
This is Henderson's first year with Team Sky.
He rode with 7-Up Maxxis in 2002-03, HealthNet in 2004-06 and Mobile Columbia-High Road in 2007-09.