Vaughan is still struggling with a hamstring injury, though England are hoping he will be fit to play against New Zealand in Brisbane on Tuesday.
"He is currently on day two of a three-day intensive training programme of full training and once he gets through that programme, we'll have a better idea of where he is," an England spokesman told reporters on Thursday.
"But the goal is for him to play on Tuesday."
Vaughan did not play for England in 2006 due to a knee injury, missing the entire Ashes series, but returned to the team for the first two matches of the Tri-Series.
England, who need to beat both Australia and New Zealand to have any chance of reaching the tournament finals, suffered another blow when seam bowler James Anderson was ruled out of the rest of the tour with a back injury.
"Whilst he is pain-free at the moment, based on specialist advice with a view to him being fully fit for the entire World Cup, he has been advised as a very precautionary approach to be rested for the rest of the series," the spokesman said.
Seamer Jon Lewis will undergo a fitness Test on an Achilles injury on Friday.
England have won only one of their six Tri-Series matches after losing the Ashes series 5-0.
