Porte was installed as the lead rider for Team Sky after Froome was forced to withdraw from the Tour having fractured his left wrist and right hand when crashing last Wednesday.
"I got a message from [Froome] yesterday, just telling me about tactics and the guys sitting on my wheel. It's nice to have support from guys like him, obviously. I'll talk to him in the next week or so," Porte told cyclingweekly.co.uk.
"The last thing he said to me before he left was that I can have these guys, to believe that. He also told other guys in the team, 'Get around Richie.' You appreciate that. Sometimes it seems that Chris has more belief in me than I do in myself. He said before the crash that we could both be on the podium.
"At Paris-Nice last year, I didn't think I was going to have that opportunity, but when I did, I had to take it. The Tour's the biggest opportunity of all of them."
Team Sky have won the last two Tours, with Froome succeeding Sir Bradley Wiggins as champion last year.