The Dutch defender has resused to sign a new contract and could leave on a free at the end of this season.
The club would have no option but to sell Loovens if a decent offer came in. It's reported that Celtic are interested after his display against them in the Algarve Challenge Cup but Rangers may storm in with a cash bid after they sold Carlos Cuellar to Aston Villa for £7.8m.
Looven's refusal to sign sends out a message that he's looking to leave for a bigger club. Cardiff have offered a three year deal with get out clauses but Loovens wants to keep his options open. Cardiff can't afford to be left pennieless when Loovens goes so the club would be right to take a possible £2.5m that's being suggested will be the offer from Rangers.
Talks had been held before about the possibility of a Loovens / Boyd switch with Rangers. No talks have taken place since then but it's widely accepted that Loovens is one of Walter Smith's top targets. Peter Ridsdale though has confirmed, according to the Echo, that Celtic have enquired.