Not that long ago, Derrick Goold of the St. Louis Post-Dispatch reported (subscription required) that the Cardinals were interested in signing star Japanese closer Yuki Matsui to bolster their bullpen. Their interest has been reported multiple times, and this could be a quick move they make in the coming week.
Why would they sign a reliever before getting their rotation in order? Well first, their bullpen is also in need of help, so it's a big need they would be filing if they pulled it off. Matsui has been excellent in Japan for a number of years now and would provide the Cardinals with another option for high-leverage situations.
Second, the Cardinals front office will be multi-tasking all offseason, and if they are able to get Matsui to commit to a deal early, there is no reason to wait. Who knows? Maybe it even helps their pursuit of Yoshinobu Yamamoto.
There is a lot of interest in Matsui around the league, but his market should not turn into a huge bidding war. His contract will be in the kind of tier where he can sign early without worrying about leaving future money on the table by jumping the market.
I think this move is possible, but I also would not be surprised to see the Cardinals prioritize starting pitching, or other organizational moves, between now and Thanksgiving.