Should i trade shaun alexander for L.moroney and roy williams from det.?

Right now that's probably an even trade. I think with Seattle's opponents for the rest of the season though, you may be better off keeping him. If you need both a RB and WR though, go for it and that person will probably jump at it since Maroney hasn't been and probably won't be any better than he is now, and Williams, while decent, does not nearly have the upside as Alexander. Good luck.