But Rizzo is far from done. The Nats are looking for a starting pitcher to join an impressive rotation that includes right-handers Stephen Strasburg and Jordan Zimmermann and left-hander Gio Gonzalez.
They are still trying to re-sign first baseman Adam LaRoche, their MVP this past season. The problem is, LaRoche wants a three-year contract. Both parties are still far apart from reaching a deal.
"If we can put Adam there, that's what we would like to do primarily," Rizzo said. "But we also have some options there if we can't get him signed. We are in an active negotiation with Adam. We had some good positive dialogue.
"We certainly respect the fact that he has earned the right to become a free agent and look at what's out there. We have not made it a secret that he is one of the primary things we are trying to do this offseason. But it has to be a fit for us financially and control-wise, and that would mean the years. He has been our priority since Day 1, so we keep talking."
Starting pitcher: The Nationals are looking for a starting pitcher to replace right-hander Edwin Jackson. Unlike previous years, Washington doesn't have pitchers from its farm system who are ready for the big leagues in 2013.
So don't be surprised if Rizzo tries to sign a veteran pitcher like free agent Zack Greinke. Rizzo tried to acquire Greinke from the Royals before the 2011 season, but Greinke used his no-trade clause to reject the deal. He ended up with the Brewers instead.
Keep in mind that Rizzo was able to acquire Gonzalez from the Athletics for four prospects late last year. Gonzalez, who finished third in the National League Cy Young Award voting, went on to win 21 games this past season.
Infield depth: The Nats are looking for a backup middle infielder. They don't consider Steve Lombardozzi or Danny Espinosa bench players. They already have signed their share of middle infielders to Minor League contracts.
Bullpen help: The Nationals would like to re-sign free-agent left-hander Sean Burnett, but they are not going to give him a three-year deal. Manager Davey Johnson loves to have lefties in his bullpen, so look for Rizzo to make a move during the Winter Meetings.
Who they can or need to trade
1B Tyler Moore: Opposing teams have already inquired about the right-handed-hitting slugger, who had 10 home runs in a limited amount of playing time. With the acquisition of Span, it will be hard for Moore to see playing time in the outfield. The first-base job belongs to Michael Morse if the Nats can't sign LaRoche.
Morse: It will depend on what LaRoche does. If he re-signs with Washington, Morse most likely will be traded. If LaRoche goes elsewhere, Morse will be the everyday first baseman.
Espinosa or Lombardozzi: The Nationals are in constant discussions on what to do at second base for the 2013 season. Will it be Espinosa or Lombardozzi? Johnson still has faith in Espinosa.
The team ended the season with the switch-hitting Espinosa as the starting second baseman, but he had problems from the left side of the plate, hitting .233 with 141 strikeouts. From the right side of the plate, Espinosa was much better, hitting .281 with 47 strikeouts. He is also a Gold Glove Award-caliber second baseman. There isn't any talk of Espinosa being strictly a right-handed hitter.
Lombardozzi, who is an excellent defensive infielder, was a backup player most of the season and hit .273 with an on-base percentage of .317. His playing time diminished once shortstop Ian Desmond was activated from the disabled list in August.
Pitchers Lucas Giolito, Matt Purke and Sammy Solis; outfielders Brian Goodwin, Eury Perez and Michael Taylor; third baseman Anthony Rendon; first baseman Matt Skole; infielder Jeff Kobernus.
During the Rizzo era, the Nationals have promoted a handful of pitching prospects to the big leagues. The Nats are expected to call up some of the position players sometime during the 2013 season. Goodwin and Rendon are two examples who could see action in the big leagues after the All-Star break.
Rule 5 Draft
The Nationals' roster is at 38 players, so they could select at least two players in the Rule 5 Draft. In last year's Draft, the Nats selected two players -- catcher Beau Seabury of the Rockies in the Triple-A phase, and right-hander Matthew Buschmann of the Padres in the Double-A phase.
Big contracts they might unload
Left-hander John Lannan made $5 million last year, but he lost his rotation spot to Ross Detwiler and spent most of the season at Triple-A Syracuse. The Nationals are not expected to pay Lannan that much money for the 2013 season.
OF Roger Bernadina ($493,500 in 2012); RHP Tyler Clippard ($1.65 million); Detwiler ($485,000); Desmond ($512,500); C Jesus Flores ($850,000); LHP Tom Gorzelanny ($3 million); Lannan ($5 million); RHP Craig Stammen ($485,000); RHP Drew Storen ($498,750); Zimmermann ($2.3 million).
The Nationals don't like to talk about payroll, but according to Cot's Baseball Contracts, Washington spent around $92 million in 2012. The Nats are expected to be postseason contenders again in '13, so look for the payroll to go up even more as they look for a starting pitcher.
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.