Redbirds was the nickname of Louisville's current AAA minor league baseball team, the Louisville Bats, from 1982 to 1998. From 1999 through 2001, the were known as the RiverBats. Starting in 2002 they dropped the "River" part opting to be just the Bats. Since 2000, the team has been the top farm team of the Cincinnati Reds.
The sweatshirt is great, but the image on the website needs to be updated. A short sleeved shirt is shown and I think that led to confusion with my initial order.