ite Structure Change = Back in the sandbox
 

I have strong feeling to believe that Google puts a website right back into the sandbox if you change your website's entire URL, Site-Map structure even though you have the SAME EXACT THEME for the site.

I have a project that was out of the sandbox, over a year old, ranking well for different phrases.

I decided I want to go into a different direction and stay in the same exact theme, but completely re-design the site, and change the URL's, folder structure, etc.

The result? Right back into the sandbox, I'm not ranking anywhere again, even for less competitive keywords. Before, I would be able to add new pages to the site and would rank for keywords that have pretty good competition, not anymore and looks like I have to wait now again.

My theory is, Google is putting sites into probation if they see a big site-wide structure change to help avoid people spamming existing domains, even if they are 'same topic/theme'.

This is just a theory though, if anyone wants to comment on this from their past experience, would love to hear it.