Robinho, who signed for City from Real Madrid in 2008 for a British record 32 million pounds, scored on Sunday in a 4-2 FA Cup win at Scunthorpe United but the 26-year-old had earlier said it would be "exceptional" to return to Santos.
"It's all on the right track. It's 90 percent certain to happen," Robinho was quoted as telling Brazilian television network Globo.
"Santos want a year but City want just six months. In two or three days, it should all be sealed."
Robinho struggled to make an impression at City under former manager Mark Hughes but Roberto Mancini, who joined the club in December, said he was keen for him to stay.
"Hopefully, in the end Robinho will stay here but it is important he will stay here, be happy and enjoy it," Mancini said.
"He is a very good player. I think he is enjoying Manchester."
Santos press officer Arnaldo Hase said the Brazilian club have sent two representatives to Manchester for talks with City on Tuesday.
"Tomorrow there will be a meeting that may be decisive for good or for bad. City would accept a six-month loan, Santos want to negotiate for six months or longer, but we will be happy if the deal is closed for six months," Hase told Reuters.
"Under our proposal, Santos would pay Robinho´s wages. The player already said to us he is open to earn less here than in Manchester," Hase added.
"If everything works out well, Robinho could be a really cheap signing for Santos because we have a lot of partners interested in financially supporting Robinho´s return to Santos."
