Span, 28, is a player the Nats have coveted since 2011. There was talk of Washington trading closer Drew Storen for Span, who has two years plus an option left on his contract.
"My emotions right now are all over the place, but I'm definitely excited," Span said in a conference call. "I feel very excited to be coming to Washington. A year-and-a-half ago, when I first heard the rumors [about being traded to the Nationals], I don't think I was ready for it. Fast forward to now, I'm definitely ready to come to a team that is in place to win. I hope that I can come here and fit in."
In 2012, Span hit .283 and led Minnesota with 38 doubles en route to notching a .342 on-base percentage. It was a comeback season after missing most of 2011 with a concussion.
"I was able to go out and prove that I can still be a good player," Span said. "Just going through [the concussion], it was probably one of the harder things I had to go through."
Span most likely will be Washington's leadoff hitter. Span is a career .284 hitter with 23 home runs, 230 RBIs, 90 stolen bases and 360 runs scored in 589 big league contests spanning five seasons (2008-12) with the Twins.
"I believe I'm a grinder. I try to bring my 'A' game every night," Span said. "I'm definitely going to bring a lot of range in the outfield. I love to go get it. I thrive to be one of the best leadoff hitters in the game. ... I love to start the game, taking pitches and ... try to set the tone."
The acquisition of Span means Bryce Harper will move from center field to left field and Jayson Werth will remain in right. Werth, who was the leadoff hitter during the second half of last year, will be moved down to middle of the order.
"I'm very excited to play with both of those guys -- two All-Star-caliber players," Span said. "I feel like I need to step my game up and try to get to the All-Star Game, hopefully. They are going to elevate my game by playing alongside them."
Nationals general manager Mike Rizzo had been talking to the Twins about Span since October. The talks started gaining momentum last week.
"Span fits very well for us. He has outstanding character, is big-time makeup guy, his teammates love him on the field, off the field. He is a big community guy," Rizzo said. "His skill set is something that we were looking for. You are talking about a true defensive ballhawk -- a center field type of guy. ... He is a front-line center fielder. He appeals greatly to us because of his skill set as an offensive player."
If the Nats are able to re-sign first baseman Adam LaRoche, they will most likely trade Michael Morse, who played left field last year. If LaRoche doesn't sign, Morse most likely will play first base. As of Thursday, LaRoche -- who is seeking a three-year deal -- and Washington were far apart.
An experienced leadoff hitter, Span has logged over 96 percent of his big league at-bats at the top of Minnesota's batting order.
Span is also difficult to strike out. In 2012, he ranked sixth in the American League by fanning just once every 9.2 plate appearances.
Span was the 10th-most difficult qualified AL player (minimum 1,000 plate appearances) to strike out the last three seasons (9.2 PA/K from 2010-12).
Dating to his rookie campaign of 2008, Span's .357 on-base percentage ranks 10th among all outfielders to amass at least 2,500 plate appearances.
Span also offers strong defensive range and advanced instincts. Last season he led all qualified center fielders in both range factor per nine innings (2.89) and putouts per nine innings (2.84).
In both 2009 and '10, Span's offensive and defensive package helped the Twins capture back-to-back AL Central titles. In six postseason contests with Minnesota, Span hit .357 (10-for-28) with a double and one RBI.
Span, 28, was born in Washington, D.C., but spent the majority of his youth living in the Tampa, Fla., area. He graduated from Tampa Catholic High School before being drafted by the Twins in the first round (20th overall) of the 2002 First-Year Player Draft.
As for Meyer, he was selected by the Nationals in the first round of the 2011 First-Year Player Draft. In his first full season of professional baseball, Meyers was a combined 10-6 with a 2.86 ERA in 25 starts for Class A Hagerstown and Class A Potomac.
Bill Ladson is a reporter for MLB.com and writes an MLBlog, All Nats All the time. He also could be found on Twitter @WashingNats. This story was not subject to the approval of Major League Baseball or its clubs.