It is believed Paul Hart wants the player, who signed for £11m in 2000, on loan but some reports have suggested a free transfer move.
His agent Andrew Blocksage told the Nottingham Evening Post: "Forest have made an enquiry but nothing has been put in writing and they have not made an official approach."
The only stumbling block could be the former Dynamo Kiev man's wages, believed to be £25,000-a-week.
The number ten shirt at Forest still remains vacant and looks likely to stay that way before the opening game at home to Sunderland.