Schalke 04 have had an improved bid for Brest's French striker Nolan Roux rejected, the German side's sporting director Horst Heldt revealed on Monday. "Our new, improved offer has been refused," Heldt said during Schalke's pre-season training camp in Austria, according to AFP subsidiary SID. If France Under-21 international Roux's chances of moving to Gelsenkirchen now appear slim, Schalke are still seeking to re-jig the attacking department of their squad. Romanian striker Ciprian Marica, released by Stuttgart last week, could join the club, although his failure to impose himself at the Swabians means "the risk has to be evaluated," according to Heldt. A decision on whether or not to sign Marica is expected to be made before the end of the week. Schalke's Brazilian striker Edu, meanwhile, could leave the club for Asia. A Japanese club are believed to be preparing a bid for the 29-year-old, who arrived from Korean outfit Suwon Bluewings in January 2010. Should Edu leave, Heldt said "it is possible that two forwards would be recruited"