You can try and contact the baseball office or just keep an eye on
www.utsports.com.
I think they usually start practice in late September or early October, and have their intrasquad scrimmages at the end of the month.
Unfortunately there aren't many home football dates after September. I don't know whether they will have started practice by the Marshall game (9/23) or not. Alabama (10/21) is the only home game in October. There's a possibility they may still be practicing prior to the LSU game 11/4.
I don't know for sure, but I'm not aware that their practices are closed.