Enough of this sitting in the dugout waiting to take the field: Washington is all fired up for baseball and this is the week to step up the chatter. What talks best in major league baseball is money -- cash on the line for tickets, and in a hurry. That's why this is "Baseball Week in Washington," duly proclaimed by the mayor. On Saturday, the team owners begin meetings in San Diego, and they're expected to talk expansion. By now they surely know that Washington, capital of the free world, is a beautiful, enthusiastic town that would give prominence to major league baseball. What they're looking for is good old green proof of that enthusiasm: a surge in ticket purchases for a 1987 season in Washington.

What a holiday gift that would be for the region: the go-ahead for a team at RFK in '87. To help make it happen, here's a money-back guarantee for every fan: open an interest-bearing baseball savings account at a participating bank or savings institution. For 10 home games, the going rate is $70; for 27 games, it's $189; and for the full season of 81 home games, $567. You may withdraw at any time. For more details, you may call 547-2077.

This is no unique approach. Twelve other areas, including Northern New Jersey, Denver, Tampa and Vancouver, are stacking up money and promises through impressive campaigns. But Greater Washington has the resources to compete, including a popular starter: President Reagan, who supports the bid and who is eager to hurl the first pitch on opening day, with strong bipartisan support in Congress.

If Washington strikes out this week, that could be it for the rest of the 20th century, maybe longer. The challenge is big and urgent. Let's do it.