Club president Giovanni Cobolli Gigli sought to ease the unrest by promising to boost the squad in the close season.
"Our directors are working in harmony with Ranieri to try to reinforce a team that did well until a few weeks ago, but then in some situations showed itself to be inferior to opponents," he told Rai television.
The Turin outfit are also at the centre of a storm caused by their fans racially abusing Inter Milan's Mario Balotelli in Saturday's 1-1 draw.
Although the insults were not of a racist nature this time, the incident will not help Juve's appeal against the stadium ban.
"I'm not going to quit. Now we must react immediately," the coach was quoted as saying by La Gazzetta dello Sport.
"It (the fans' protests) does not please us. But we're fighting, doing our best. We have to know how to accept both compliments and criticism."
Sixth-placed AS Roma visit fifth-placed Fiorentina on Saturday in an important match in the race for Italy's fourth Champions League slot.
