Sadiq, 21, spent the 2017-18 season on loan at NAC Breda in the Netherlands, and is set to go on another temporary switch as Roma look to give their prospect the chance for regular first-team football.
And he affirmed that the presence of the former Liverpool star Gerrard as manager was a big factor in his decision to move to Ibrox.
“It is very good to be here, it has been good so far and I can’t wait to start. I truly am excited to be joining Rangers, it is a historical club and I can’t wait to play here," he explained to Rangers TV .
“I found out Rangers were interested in me about a month ago when I was on holiday in Nigeria. I got a phone call from my agent and he told me about Rangers and I said let’s see what happens.
“He called me about two weeks ago and from there I started changing my mind. To be honest the plan was to stay at Roma this season but when Steven Gerrard calls you can’t say no.
“He told me about the team; even though I already knew about Rangers and that they are the most successful team in the world.
“He told me about the players and said everybody would be at my side if I came here to help me and he would also help me to go forward in my career."
The Nigeria Under-23 international has drawn comparisons to the likes of Nwankwo Kanu, but he insists he does not feel the pressure of living up to such a high example.
“I don’t like to say anything about myself but I am a hardworking player who always wants to help the team," he added.
“I am just myself, even though in Nigeria I am compared to the legend Kanu and Emmanuel Adebayor. It is an honour when someone talks about Adebayor or Kanu next to me.
“In football you never know what is going to happen but hard work pays and with the work I am going to do here I think I will be successful.”