Yes, the term taxi squad was defined in the operation regulations that MLB put out but the term has and continues to be misused to apply to the group at the Alternate Training Site. Originally, the taxi squad was 3, one of whom had to be a catcher. It is now 5, if I remember the latest I've read on it.
I suppose that if they expand, they might add a few more players from the system to give them the chance to work out and play intersquad games at Coca-Cola park. They also could sign a couple players who have been cut and are looking to hook on somewhere.
Players like Roberston, when he is getting closer to coming off the IL (if that happens this year), could also end up at the ATS.
I noticed that the Cardinals only had 5 games played going into today. They must have a ton of double headers coming up.