The 34-year-old missed Red Bulls training on Monday, despite returning to action as a substitute in last week’s win over Philadelphia Union.
Cahill underwent further treatment on the minor hamstring strain, which he sustained late last month against Chivas USA, instead of training.
Petke revealed Australia’s all-time leading goal scorer, who’ll play a key role for his country in Brazil in two months’ time, wasn’t 100 per cent fully fit after the injury.
"We'll wait until tomorrow to figure that out with Tim but Tim needs to feel 100 per cent before he comes back, for his sake and for our sake," Petke told reporters after training on Monday.
"So it's important that we get him back. Having said that, we'll figure it for tomorrow and do what's best for him and the team.
"As you saw he did get some minutes against Philly but if he's not feeling 100 per cent, we need to protect him and protect us."
New York are next in action on Thursday (9.30am AEST) when they host Houston Dynamo at Red Bull Arena.