The Old Lady have had a poor start to the season and lost again on Saturday against Napoli.
Juventus are currently on 12th place in the Serie A.
“Ranieri? Faith is given one time and the club has already done so,” Blanc told Sky Italia.
“It’s a tough time. We’ve set an objective of returning to winning ways as soon as possible so that our confidence returns.
“I saw an aggressive Napoli, we made some mistakes in defence. We know we have to work hard.
“We also need to take into account the list of injuries, it’s not an excuse, but we’ve paid a very high price.”