The Mali international spent the second half of last season on loan at Fiorentina before agreeing to have his contract terminated with French champions Paris Saint-Germain.
Sissoko, who worked under Ranieri at Juventus, is currently training with the principality outfit and suggested he will hold talks with the club in order to make his move permanent.
"I asked to come and train here. I know Ranieri well. He coached me at both Valencia and Juventus," Sissoko told the official Ligue 1 website.
"It's quite complicated. The club and I will talk later."
Monaco have made an unbeaten start to life in France's top flight since winning promotion last season and currently sit top of the standings on goal difference ahead of PSG.