Jenny Dell is a CBS NFL reporter and she's also the hot wife of recently called up Brewers third baseman Will Middlebrooks, which explains why she was at Miller Park.
Seeing as how Will has only played 10 games at the MLB level this season, I'm going to guess her access to the Bernie the Brewer slide has more to do with who she is and not Will's current status with the big league squad. That ought to go over well with the other player's wives.
As for the slide, Dell knocked it out of the park. Her short striped dress didn't hurt.