PWTorch is reporting that the first two TNA "BaseBrawl" venues have been confirmed. The first will be held on May 6th at the Rawhide Ballpark in Visalia, California. The second will be held on August 17th at the Appalachian Power Park in Charleston, West Virginia.
There will likely be dates and venues confirmed soon, to be added in between these two dates. As of now these are the only announced and advertised TNA "BaseBrawl" events.
