Sneijder, a standout player in their 2010 treble season but who is reportedly Inter's top earner with a €6m annual salary, again looks set to be left out of their match with Palermo on Sunday.
"Sneijder isn't playing because the coach doesn't think he's at his best, above all psychologically," said Inter president Massimo Moratti.
"For us it's natural to look for a way to not be forced to sell him and he has the right to not accept our offer. If it stays like that, the solution will be on the transfer market."
Inter are without a win in three games after Monday's 1-0 defeat at Parma and have dropped down to fourth place, but are only four points behind leaders and champions Juventus.
Sneijder has been linked with moves to both Manchester clubs and Paris St Germain.