The first post of the Prototype Uniforms series is for the San Diego Padres. The jersey is from 1999, and is navy with white and sand accent colors. It features a new San Diego wordmark, which was eventually used on their road jerseys, still worn today. The jersey also has an iteresting alternate logo on the sleeve, a P with a palm tree inside. The only part of this jersey that was actually used is the wordmark, which was modified and first used in 2004.
Photo credit of Bill Henderson, of www.mlbstyleguides.com