The Nationals would like to add a durable, veteran starter. like free agent Kyle Lohse. (John McDonnell/THE WASHINGTON POST)

The gears of the baseball offseason began churning this weekend, and free agency coughed and sputtered to a start for the Washington Nationals and the rest of the major leagues. At 12 a.m. Saturday, any team became welcome to sign any free agent, and the Nationals’ many options on the open market sprung to life.

The Nationals have several needs in free agency, primarily finding a fifth starting pitcher after they declined to give Edwin Jackson a one-year qualifying offer, signaling their intent to cut ties with the 29-year-old right-hander. But the Nationals won 98 games and claimed the National League East with a young, mostly homegrown roster, and so making minor tweaks rather big splashes is a viable choice, too.

The Nationals will enter a free agent market that may seem overactive compared to recent seasons. The league is flush with cash because of new television revenue and rising attendance figures. Fewer stars are available than usual because of the growing trend toward teams signing marquee players before they reach free agency. It will be a whole new brand of free agency.

But there are plenty of valuable free agents, and the Nationals will enter the fray with several goals in their effort to go from National League East champion to World Series participant. They would like to re-sign free agent first baseman Adam LaRoche, who has until Friday to accept the one-year, $13.3 million qualifying offer the Nationals made him. They need to add a starter, preferably a reliable veteran who wouldn’t require a long-term commitment. They need to beef up their bullpen. They may try to solve their years-long search for a solid center fielder

The offseason will hinge partly on whether they can re-sign LaRoche. The sides have engaged in contract talks since the end of the regular season. LaRoche wants to stay in Washington, but he will likely decline the qualifying offer in the hopes of landing a multiyear deal.

If the Nationals cannot re-sign LaRoche, they could move Michael Morse to first base and begin the search for a center fielder, moving Bryce Harper to left field to save him from the wear and tear of playing center field.

The best free agent center fielders available are Michael Bourn and B.J. Upton, both of whom the Nationals have discussed in trade talks in recent seasons. Bourn is the superior defender, but both play top-shelf defense. Upton hit 28 homers in 2012 and provides above-average power for a center fielder, while Bourn has the on-base skills to lead off and let Jayson Werth hit in the middle of the lineup.

Bourn could require a four- or five-year salary somewhere between $80 million and $100 million, while Upton, who played youth baseball with Nationals third baseman Ryan Zimmerman, would likely take at least a three-year contract. Signing either would give them a quality player as well as weaken the Braves and Phillies, two divisional rivals in need of a center fielder.

Still, the Nationals may not be as keen on giving that kind of deal to a center fielder as many expect. Harper played well in center in his rookie season, and they have a center field prospect in Brian Goodwin who could handle the position not this season, but in the near future.

There is another marquee name to keep in mind, not on the free agent market but on the trading block. The Nationals attempted to trade for Red Sox center fielder Jacoby Ellsbury this summer, putting in a waiver claim for him in August, according to a person with knowledge of the situation. It is not known what the Nationals offered, only that they fell far short of the Red Sox’s understandably high demands, and the discussions never reached advanced stages. But it would not be a surprise if they tried again for Ellsbury, who would become a free agent after 2013, if the Red Sox make him available (and that’s a significant “if”).

If the Nationals sign LaRoche, they could essentially keep the same lineup from last season. Or they could also trade Morse, who will make $6.75 million in his final season before free agency, and acquire a top-flight center fielder.

The Nationals made their rotation plans clear when they did not give Jackson a qualifying offer on Friday night — they want to add a fifth starter from outside the organization. For now, people familiar with the Nationals’ thinking expect them to either trade arbitration-eligible John Lannan or allow him to become a free agent. Manager Davey Johnson raised the possibility of converting standout call-up Christian Garcia from a reliever to a starter, but his inexperience and history of arm injury may make that too risky.

With a young staff, the Nationals would like to add a durable, veteran starter. Free agents Kyle Lohse, Ryan Dempster and Dan Haren, whom the Los Angeles Angels let go after he struggled through a lower-back injury in 2012, all fit the mold.

Lohse, a Scott Boras client, is coming off the two best seasons of his career and would demand a contract of three or four years, which may be more than the Nationals are willing to commit with top prospect Alex Meyer a possibility for the 2014 rotation. Dempster would require less money and fewer seasons. Haren may be the best fit, a No. 2-caliber starter if he can rebound from the injury. He averaged 226 innings per season with a 3.49 ERA from 2005 through 2011.

In the bullpen, the Nationals’ top two left-handers, Sean Burnett and Michael Gonzalez, are free agents. The Nationals plan on trying to re-sign Zach Duke and giving him the left-handed long-relief/spot starter role filled by Tom Gorzelanny last season. The move could let them trade Gorzelanny for another piece or to keep Gorzelanny, who is eligible for arbitration, and make him into a left-handed specialist.

If the Nationals cannot re-sign Burnett, who will be sought-after, they could target Jeremy Affeldt to replace him. Affeldt is older than Burnett, but has been similarly productive in recent seasons and, like Burnett, is effective against left-handed and right-handed hitters.

The Nationals may also try to enhance the back-end of their bullpen. Ryan Madson, a former Phillies closer coming off Tommy John surgery, is a possibility if they decide they prioritize putting another power arm with Tyler Clippard and Drew Storen.

Despite all the chatter, the Nationals have the option to prune their roster, not overhaul it. But the past two offseasons have both brought surprises — Werth’s megadeal prior to 2011 and Jackson’s late signing before 2012. It’s probably wise to expect something unexpected.