Niculae joined the SPL club last summer on a two-year contract and his form earned him a recall to the Romania squad for Euro 2008.
Dinamo Bucharest and Karlsruhe are reported to have bid for Niculae, but have yet to meet Inverness' valuation of the 27-year-old.
Caley Thistle vice-chairman Graeme Bennett told the Press and Journal: "We have had a friendly and constructive discussion with Marius.
"We informed him that we had received offers from two clubs for him and we had rejected them as they did not meet a realistic valuation.
"Marius indicated that if any further offers came in he would wish the opportunity to consider them.
"The club has agreed to inform him of any such offer that is acceptable to us and then to allow him to talk directly to a club which has tabled an offer.
"In the meantime he has begun training with the first-team squad and will be available for selection until or unless we receive an offer which is satisfactory."