Lerner Enterprises, the D.C.-area development company recently named the new owner of the Washington Nationals, on Monday announced plans to develop an 18-story, 472,000-square-foot office building in the Tysons II area.

The office building — which is scheduled for a summer 2009 delivery — is the fifth proposed for a 5 million-square-foot mixed-used development that is part of an overall development strategy to convert Tysons from acommuter destination to a pedestrian-friendly, livable community.