The 26-year-old Real Madrid centre-half, who left the Whites for Newcastle in January 2003 under Terry Venables, before clinching a £13.4m move to the Bernabeu in August 2004, is currently enjoying a break from his daily fitness routine in Madrid.
"He's over here for a few weeks and has popped into to catch up with old friends," said a Leeds spokesman.
"He's still injured, so while he's here he's having a bit of treatment from our physio Dave Hancock."