Definitely looks like something to check out if your a baseball fan, also looks like it's very family friendly, you could definitely make a day or weekend out of it.

America's Center
701 Convention Plaza
St. Louis, MO 63101

Friday, July 10: 9:00AM-7:00PM
Saturday, July 11: 9:00AM-8:00PM
Sunday, July 12: 9:00AM-8:00PM
Monday, July 13: 9:00AM-8:00PM
Tuesday, July 14: 9:00AM-6:00PM

Tickets and more information available here :

Autographs, merchandise, games, etc.