Take a look at this photo from 2005 taken from the top of the St. Louis Arch. The stadium the Rangers are playing in now was under construction at that time right next to the circular stadium that would soon be torn down. But look how close they are. In fact, that circular stadium even protrudes into what looks to be left field of the new stadium. I guess they built as much as they could, blew up the old stadium, and finished the new.
Edit: And how it looks before Game #2