The 26-year-old has established himself as an important player for the Ibrox outfit and is the first-choice goalkeeper for the Scottish Premiership outfit at the moment.
It was Warburton who signed Foderingham for Rangers from Swindon Town when he was in charge of the Glasgow giants.
The Englishman has expressed his admiration of the former Fulham and Crystal Palace prospect, but the Forest manager has refused to give a straight answer when asked if he is interested in signing him in the summer transfer window.
“We are very close with one and there may be one more after that,” Warburton told The Scottish Sun when asked about any interest in Foderingham. “We will see.
“He is one of only 49 players we have been linked with this summer, isn’t he? But we signed him at Rangers and I have a lot of respect for him, which started before that, from his time at Swindon.
“He is a Rangers player. I have enormous respect for him, because he is a tremendous keeper. But he is a Rangers player and I do not like to talk about players who are at another club.”
Forest kicked off their 2017-18 Championship campaign with a 1-0 victory over Millwall at the City Ground last week.
Meanwhile, Rangers won 2-1 against Motherwell away from home last weekend in their opening game of the 2017-18 Scottish Premiership season.