It appears that White Sox fans are concerned with Erstad blocking Brian Anderson or Ryan Sweeney.  Most of them are expecting him to be a fourth outfielder, but reality says otherwise.  Guillen will most likely start him in CF, at least until the kids prove they are ready.  It's interesting to note that some of them believe that Erstad is only "slightly above average" defensively.  Here's the link to the discussion:

http://www.southsidesox.com/story/2007/1/23/175130/261#commenttop