The team has already stated that they are going to take their time, at least until the end of the year, to make the decision. That is an example of the St. Louis Cardinals front office being smart. See how the team plays outside of the Mike Matheny era, then make the decision about the direction of the team.
The second half will say a lot. If the team trends downward, it might mean a rebuild. However, if the team surges their way to a playoff run it will bring hope for the next season.