Sandy Leon will make his major league debut tonight as the Nationals host the Padres in the first game of a brief two-game series. He'll catch and hit eighth. Weather permitting, the game begins at 7:05 p.m. Here's the Padres lineup: CF Cameron Maybin RF Chris Denorfia LF Jesus Guzman 1B Yonder Alonso 3B Chase Headley C Nick Hundley 2B Orlando Hudson SS Jason Bartlett P Tim Stauffer Here's the Nationals lineup: SS Ian Desmond LF Roger Bernadina 3B Ryan Zimmerman 1B Adam LaRoche RF Bryce Harper 2B Danny Espinosa CF Rick Ankiel C Sandy Leon P Ross Detwiler