Rangers boss Ally McCoist has spoken of his liking for Neil Danns, while Celtic are also thought to be interested in the playmaker.
As revealed by skysports.com, Rangers have joined the chase to land the 28-year-old, who is available on a free transfer as his current deal with Crystal Palace is due to expire.
But Old Firm rivals Celtic are now also thought to be weighing up whether to launch a move for the midfielder, who has also been linked to Southampton and Hull City.
Speaking of his liking for Danns, McCoist told the Daily Mail: "I think everyone accepts we need more numbers in our squad. We need more strength in depth.
"I would describe Danns as a box-to-box midfielder with good physical attributes and he should be suited to Scotland."
Meanwhile, French outfit Le Mans say they would listen to an offer from Rangers for Marcelo Estigarribia.
The Paraguayan, who would provide options for McCoist in left midfield or on the wing, was Le Mans' record £2.7million signing three years ago but made only 12 first-team appearances before being loaned to Argentinean side Newell's Old Boys.
His loan ends on 30th June and Le Mans spokesman Guillaume Bertel said the Ligue 2 outfit would listen to offers on the player, who has a year left on his contract.
Bertel told the Daily Record: "We have not yet had any direct contact with Rangers over the sale of Marcelo but if they are interested then the door would be open for them.
"He has not featured for us for almost two years. He failed to settle to life in France and adapt to the physical nature of football here and it was best for him to go to Argentina.
"He has a year left on his contract and we are open to a transfer. It will be best for him and best for us and we will not be difficult to deal with.
"He cost us around three million euros when we bought him. He was a big signing with a lot of potential and there is no doubting he has natural ability but we will be realistic if a fair offer comes in. We will listen to whatever Rangers have to say."
Bertel added: "Technically, Marcelo is very good. He's a very good passer of the ball and always likes to pick out a long pass.
"He can play anywhere from No.6 to No.10 and likes to dictate play from the middle. He can also play wide because of his pace so he's useful for the right club."