For some players, it doesn't always work out once they get to the major leagues. Sometimes a move overseas can resurrect their career.
The Cardinals are always active when it comes to international free agents that have past major league experience, or experience in another country. Just in the last few years, we have seen Sueng-Hwan Oh, and Kwang-Hyun Kim come to the States after being stars overseas. And then we've seen guys like Andrew Suarez, Drew VerHagen, and Miles Mikolas that went overseas to add something to their game hoping to make it back to the MLB someday.
The benefit of signing international guys is the lack of risk involved. You can usually sign them for cheap, and bet that they evidently did revive their careers playing in a different country and produce. Oh ( aka Stone Buddha ) and Kim saw success in the MLB, especially in their first years with the Cardinals. Mikolas was the Cards' Opening Day starter this year, and VerHagen has become a reliable reliever when healthy.
There are a few players that used to play for the Cardinals that are trying to make a comeback to the big leagues as well. Here is a list of some familiar names.