Ivan Navarro Pastor comes to my mind when we are talking about "lower ranked Spanish player who is not TOP 100 anymore and is getting older". While watching him I sometimes had a feeling...Although I didn´t notice he is disliked here, so I am probably wrong(?).
EDIT: When you are mentioning Robredo, I actually read rumours about him. Don´t know if it´s legit or not though.
It really can only be Navarro. The only other active player who has been in the Top 100 is Pere Riba, but he isn't nearing 'old age'. The problem with Navarro is that a) he is unnoticed rather than disliked, and b) he doesn't have a history of frequent injuries.
Perhaps these cryptic clues can be put to rest by just naming someone, especially as it apparently is 'common knowledge'