Adam LaRoche is seeking out a market of interested teams to determine what the price for the Nationals to sign him would be. (John McDonnell/The Washington Post)

On the first day of Major League Baseball’s general manager meetings here, fellow executives walked up to Mike Rizzo in the halls and conference rooms of the Hyatt Regency and offered congratulations. In his fourth appearance at the annual meetings, Rizzo was coming off not only his first winning season as the Washington Nationals’ leader, but a 98-win regular season that left the Nationals with the best record in baseball. “They seem to be happy for us,” Rizzo said.

As Rizzo and the Nationals’ front office have started to shape the contours of their offseason, they are focused on the best way to improve a dominant regular season team. While the Nationals’ young roster sets them up for continuity, Rizzo on Wednesday did not rule out reshaping the team as he publicly outlined his offseason outlook for the first time. As the dominoes fall this winter, the 2013 Nationals could look very similar to or quite different from the 2012 version.

“We have a plan that has some tweaks to it,” Rizzo said. “We have some plans that, if it works out, you could do a more impactful addition to the club. We’re open for any or all type of situations that help us get better.”

The Nationals’ various scenarios hinge on what happens with first baseman Adam LaRoche. The Nationals and LaRoche’s representatives from his agency, SFX, have been in touch multiple times since the end of the season, Rizzo said, but the sides are currently allowing LaRoche to seek out interested teams and determine what the price to sign him would be.

Rizzo wants to bring LaRoche back after he hit 33 home runs and won a Gold Glove. He also became a solidifying clubhouse presence, and his left-handed bat fit perfectly into the middle of the Nationals’ lineup. But “we have other options, so that makes it less critical” to re-sign him, Rizzo said.

The Nationals could move Michael Morse to first base. The possibilities then become boundless. The team feels Tyler Moore has the ability to be an everyday player, and they could simply move him to left field. More likely, Washington would try to acquire a high-impact outfielder. Rizzo said he would feel comfortable leaving Bryce Harper in center field and Jayson Werth at leadoff next year, and so they could add any kind of player in the outfield.

They could vie for a center fielder who flies around the outfield and reaches base often, such as Michael Bourn. Or they could try to trade for a slugging corner outfielder such as Justin Upton of the Arizona Diamondbacks. Rizzo drafted Upton with the first overall pick when he served as Arizona’s scouting director.

“Good impact players are attractive to us and we’ve got the flexibility that we’re not keyholed into center field, leadoff, first base,” Rizzo said. “We’ve got a team that’s versatile enough that we can look at a broader picture and get an impact player for us if his skill set fits our club. We don’t necessarily have to look at a leadoff-center fielder like we did a couple years ago because we can move Harper to the corner, get a guy in center, keep Harper in center, get a corner guy, keep guys in the corner, stay with the team we have. There’s a lot of things.”

The most straightforward piece of the Nationals’ offseason is filling out their starting rotation. The Nationals effectively moved on from Edwin Jackson when they did not offer him a one-year, $13.3 million qualifying offer last Friday, a signal they would rather lose him without receiving a compensatory draft pick than risk him coming back at that price. Rizzo simply saw more desirable options on the free agent market.

“Those are decisions that you talk about internally,” Rizzo said. “We felt with the depth we had at the major league level and the depth of free agents that we had out there that we had as good or better options.”

While the Nationals have in-house options — they still have John Lannan under team control and September call-up Christian Garcia will convert from relieving to starting — Rizzo seems intent on adding a starter in free agency.

Last year, the Nationals made Mark Buehrle their top free agent target before he ultimately chose the Miami Marlins’ more lucrative offer. Rizzo coveted Buehrle for his experience and durability. This winter, though, Rizzo will aim higher when he tries to add a starter.

“I’m much more open-minded with it this year,” Rizzo said. “It doesn’t necessarily have to be a veteran, it doesn’t have to necessarily need to be a fifth-starter type of guy. We just want to get the most quality type of pitcher that we can.”

Rizzo also said the matriculation of their top pitching prospects, led by Alex Meyer, would not inhibit them from signing a starter to a multiple-year deal. Essentially, Rizzo will not limit the scope of his search for a fifth starter in a free agent market that includes Zack Greinke, the former Cy Young winner whom the Nationals nearly traded for in December 2010.

“It would depend on the price, of course,” Rizzo said. “But we’re not in the market for a quote-unquote fifth starter. We want to get as good of a starting pitcher as we possibly can. He may pitch fifth in our rotation, but we don’t necessarily want a No. 5-quality starter.”