Inter - who host Bologna on Friday - clocked up seven wins in a row in December and January, moving them within five points of leaders Milan.
But they have taken one point out of 12 since then, dropping 11 points behind champions Milan and slumping back into fifth place while also getting knocked out of the Italian Cup by Napoli.
More worryingly for their fervent band of supporters on San Siro's Curva Nord, they are six points adrift of Lazio who are third and occupy the Champions League play-off spot.
"The players and the coach are all under the microscope," Ranieri said at his pre-match news conference on Thursday. "It's natural that president [Massimo] Moratti wants us to win and progress.
"The matches which are just behind us were not inspiring, we took some knocks which left us on the deck. Now, we have to reverse the trend."
Inter slumped to a 1-0 home defeat against bottom club Novara on Sunday and the hardcore fans called for former Juventus and AS Roma boss Ranieri, only appointed in September, to be replaced by ex-England manager Fabio Capello.
"It is important to support the young players, when there are rumblings of discontent at San Siro, the experienced players keep running but younger players can be affected by it," Ranieri added.
"Football is not always an exact science. Against Novara we played well but they hurt us with one counter-attack.
"We'll have to be more careful on Friday, because Bologna will try to attack on the break too."
It has been a topsy-turvy season for Inter, who fired Gian Piero Gasperini after only five games before turning to Ranieri.
He began with a 3-1 win at Friday's opponents Bologna, suffered three defeats in their next five games and then oversaw a big revival before presiding over a new slump.
Milan, who top the table with 47 points from 23 games, visit relegation-threatened Cesena buoyed by their Champions League thrashing of Arsenal but with Zlatan Ibrahimovic suspended.
Juventus, a point behind in second place with a game in hand, host Catania having drawn 0-0 at Parma on Wednesday. Lazio, third with 42 points, head to Palermo.
