The Brazilian club's vice-president has called for the forward to reduce his salary demands as negotiations continue over a move back to Brazil
The Brazilian club are eager to tie up a deal for the AC Milan forward - whose contract expires in 2014 - and appeared to have overcome their biggest hurdle after the Serie A side reportedly agreed to drop their €10 million [£8.6m] valuation to €8.5m [£7.3m].
But negotiations could be set to stall yet again after Santos admitted they need Robinho to take a pay-cut in order to complete the deal.
"I hope Robinho will lower his wages again," Rodrigues told Gazeta Esportiva.
"Milan have set a very high valuation on the player and we hope this can be cut to make the operation more do-able."
The 29-year-old scored just two goals in 23 Serie A appearances last season and found himself on the fringes of the side for much of the campaign.
Robinho began his career at Santos before joining Real Madrid in 2005 and then Manchester City three years later. He returned to Santos for a loan spell in 2010 but moved onto AC Milan in a permanent deal later that year.