The 21-goal frontman, who attracted significant interest in the January transfer window, has been the subject of bids from two League One clubs, one verbal and one written, with both having made offers earlier in the season.
A further bid from a League Two club, believed to be Swindon, is expected to come when the season closes, though Crawley, who made a bid in January when Millers boss Steve Evans was in charge there, have not renewed their interest.
"He is a really gifted boy who can do the most magical things," Evans said. "Lewis is a very good footballer and we want him here. It doesn't mean that he is going to go.
"The board will make a decision if these offers are expected and if they are I will sit down with him but until then he doesn't have a say in it.
"In today's market he is worth about £300,000 or £400,000 in my opinion, but it's not about the money here. It has to be right for the club and if any offer was accepted the chairman has assured me I'd get the money anyway."