Phelan M. Ebenhack / AP

The first major domino of baseball’s free agency fell last night, and it left a mighty imprint in the National League East. The Atlanta Braves agreed to terms with former Rays center fielder B.J. Upton, according to multiple reports and, in a sign of the times, the avatar on Upton’s Twitter account.

The reported five-year, $75 million deal places a 28-year-old with a thunderous bat and a sprinter’s grace in the Nationals’ division for the next five seasons. Upton never seemed to reach his full potential in six seasons in Tampa, reaching base at a subpar rate and striking out with great frequency. But he slugged 28 homers in 2012 and plays outstanding defense in center field — not as well as Michael Bourn, the man he will replace, but close. The Braves were an NL East contender in 2012, and Upton, a Little League opponent of Ryan Zimmerman, will only help them take aim at the Nationals in 2013.

The Nationals had at least some initial talks with Upton, and now one of the possibilities to fill an outfield spot for them should Adam LaRoche sign elsewhere, and trigger Michael Morse’s move from left field to first base, is gone. But several options remain if the Nationals lose LaRoche and test the market for an outfielder.

The Nationals will of course be linked to Bourn, the Scott Boras client they tried to trade for at the 2011 deadline. The Nationals, though, may not be inclined to give Bourn the five-year contract he desires. They have Brian Goodwin approaching the majors, and a long-term deal with Bourn would block their best outfield prospect. But his hitting is nominal — a 98 OPS+ over the past three seasons — and he turns 30 in December, a red flag for any player who relies on his legs.

There are also plenty of reasons for them to pursue Bourn. He plays defense like a wizard and steals bases as well as any current major leaguer. While the final years on  his deal may not seem attractive, the Nationals are in position to field a World Series contender, and Bourn’s defense and leadoff ability would be a compelling fit.

In the LaRoche-leaves scenario, the Nationals have other options. Angel Pagan is a free agent after helping the Giants to the World Series title this October. Denard Span, whom the Nationals tried to pry away from the Twins in 2010, could be traded. Both players would fill the center field/leadoff requirement without providing a long-term commitment.

The derby for center fielders will continue to play out primarily in the National League East. The Philadelphia Phillies need a center field, too, and the Nationals could find themselves competing with their most bitter rival for the same set of players.

The Nationals do not have to dive into the center field market, even if LaRoche signs with another team. They could vie for a corner outfielder and keep Bryce Harper in center fielder for at least one more season. They could also play Tyler Moore, who showed big power in limited playing time as a rookie, in left field.

The Nationals have already watched one impact player land in their division. They can’t sign Upton any longer, but they will be dealing with him for years to come.