“I’m going to bring a lot of range in center field. I love to go get it,” Denard Span said. (Hannah Foslien/Getty Images)

The Washington Nationals ended their long-standing search for a center fielder and leadoff hitter at the substantial cost of their best pitching prospect, acquiring Denard Span from the Minnesota Twins for minor league starting pitcher Alex Meyer in a trade that shapes the rest of their offseason.

Nationals General Manager Mike Rizzo saw Meyer, a 6-foot-9 right-hander with a 99-mph fastball, as Washington’s next great homegrown arm. But Rizzo also wanted a chase-everything-down center fielder and a speedy, on-base machine at the top of the Nationals’ lineup. He pined for Span, a 28-year-old with an affordable contract. The Nationals nearly dealt for Span at the 2011 deadline.

“My emotions are all over the place,” Span said. “Definitely exciting, man. I’m very excited to be coming to Washington. A year and a half ago, when I first heard the rumors, I don’t think I was ready for it then. Now I’m definitely ready for it.”

Since the franchise migrated from Montreal in 2005, the Nationals have sent 32 men to play center field. But only now, in a move that will trickle down their roster, do the Nationals have their center fielder. The position the Nationals couldn’t solve now belongs to Span.

“I think he’s going to bring a dimension to the club that we haven’t had before,” Rizzo said. “His skill set is something we were looking for, something we’ve been looking for, for a couple years. He’s a front-line defensive center fielder. He’s a consummate leadoff-type of hitter.”

With Span in center field, Bryce Harper will move to a corner outfield spot full time. Rizzo said he wanted to remove the “physical” and “mental” strain of playing center from Harper. Rizzo, somewhat surprisingly, said the Nationals would sort out which outfielder plays which corner in the spring between Harper and right fielder Jayson Werth.

The Nationals can now move on to answering the next questions of their offseason. To set their lineup, they have two options: re-sign first baseman Adam LaRoche and trade left fielder Michael Morse, or keep Morse and let LaRoche, a key cog of the Nationals’ 98-win season, sign elsewhere.

“It gives us some options in dealing with our roster,” Rizzo said.

Rizzo said the Nationals have continued discussing a contract with LaRoche, who this year hit 33 home runs and won both a Gold Glove and Silver Slugger award. LaRoche wants to return to Washington, but the Nationals have not yet offered LaRoche more than a two-year contract. LaRoche could expect a longer deal after his excellent 2012 season.

“I think this is a hell of a move, because it gives us some protection if Adam leaves,” Manager Davey Johnson said. “I’ll still have some left-handed presence in the lineup.”

Span will make $11.25 million combined over the next two seasons, with a $9 million team option for 2015. The contract seems friendly compared with the five-year, $75 million deal the Atlanta Braves committed to for B.J. Upton. Span’s contract will prevent him from blocking Brian Goodwin, the Nationals’ top outfield prospect, if and when he is ready for the majors.

Span’s contract also could allow the Nationals to allocate a bigger chunk of their payroll to acquiring a starting pitcher to replace the departed Edwin Jackson or to acquiring bullpen help. The Nationals could also use Morse as a trade chip for either aim, if they re-sign LaRoche first.

One agent, who has no involvement with Span, said his presence may help the Nationals acquire a starter. With Harper, Werth and Span, the Nationals now have one of the best outfield defenses in the majors to go with their athletic infield defense. If LaRoche re-signs, it would not be a stretch to say the Nationals have a possible Gold Glove candidate at seven or eight positions.

“I definitely believe I’m a grinder,” Span said. “I love to have fun. I try to bring my ‘A’ game every game. I’m going to bring a lot of range in center field. I love to go get it.”

The Nationals will place Span at the top of their lineup, allowing them to slide down Werth and perhaps Harper, too. Depending on whom they choose at first base, Werth could hit second and Harper, after batting second most of last season, could hit “anywhere from second to fifth,” Rizzo said.

Span gives the Nationals a prototypical leadoff hitter they have never had before. He has a .357 career on-base percentage, which topped out at .392 in 2009. His numbers dipped in 2011 as he dealt with symptoms from a concussion, which led to blurred vision and headaches. Nationals team doctors reviewed Span’s medical history before the team agreed to the trade, Rizzo said.

“I am confident I’m behind it,” Span said. “I feel like last year was a good sign of it. I was able to go out and prove I could still. It was probably one of the hardest things I’ve had to go through.

“The reason why I wasn’t ready [to be traded] a year and a half ago was because I was going through the concussion at the same time. Fast forward to today, I’m definitely ready.”

Late Thursday afternoon, Span spoke with Twins General Manager Terry Ryan, a sad conversation that ended his 10 seasons with the organization. Minutes later, he spoke with Rizzo, the man who tried for 11 / 2 years to bring him to Washington.

“That’s the greatest feeling any ballplayer can have, when you’re wanted,” Span said. “When a team does whatever it has to do to get you, it’s a good feeling. I could hear it in is voice, how excited he was. It gave me some life.”

Rizzo had given up a great deal to acquire Span. The Nationals drafted Meyer in 2011 with the 23rd overall pick, one of the choices they received in compensation for Adam Dunn signing elsewhere. (They used the other pick, incidentally, on Goodwin.) In 25 starts this year between Class A affiliates in Hagerstown and Potomac, Meyer struck out 139 in 129 innings with a 2.86 ERA and 45 walks.

“We understand the process,” Rizzo said. “To get a good, established player at Denard’s age, with the contract he has, you have to give up a quality player. We feel we have great depth in our minor league system.”

Span has a unique personal history with Washington. His mother, Wanda Wilson, went to UDC and his uncle, Wilson’s older brother, lived in Washington. While she was pregnant, Wilson visited Washington from her home in Florida. She had no plans to deliver her child away from home, but “I ended up just popping out early on,” Span said.

The Nationals’ new center fielder was born in Washington, raised in Florida and reared as a professional in Minnesota. After a pursuit that took years, Span is now back, part of the Nationals’ plan to move from contender to champion.