Ross D. Franklin/AP

Barring any hold-ups, right-hander Dan Haren will join the Nationals’ starting rotation next season; all five of the spots would be filled. The move essentially takes them out of the sweepstakes for top free agent pitcher Zack Greinke, a name commonly linked to the Nationals, and saves them considerable money. An already strong starting rotation will now consist of Stephen Strasburg, Gio Gonzalez, Jordan Zimmerman, Ross Detwiler and Haren.

With the agreement with Haren, one of the Nationals’ needs entering the winter meetings in Nashville this week has been filled, and now two pressing matters remain: adding to their bullpen and determining who will play first base next season. Here’s a look of the ripple effects of Haren’s deal, and what remains.

>>> Is Haren better than Edwin Jackson? The Nationals are taking a risk on Haren, 32, agreeing to pay him $13 million for one season, but it’s limited. Last season, they paid Jackson $11 million for one season and the right-hander had no major injury history. This time, there was concern about Haren’s lower back stiffness and hip, which some teams feared. The Nationals passed on Jackson, not extending a qualifying offer and opting for the free agent and trade market instead.

And, it may just work out with Haren. He and Jackson both debuted in 2003, but Haren’s resume is better. He has a lower career ERA (3.66) than Jackson (4.40) and a better adjusted ERA+, 116 versus 98, respectively. Haren isn’t the power arm like Jackson, relying instead of a 90-91 mph fastball and cutters and split fingers to get batters out. But even then, Haren has a better career strikeout per nine inning ratio (7.6) than Jackson (6.9). Haren, a three-time all-star who finished in the top seven in Cy Young voting twice, also has better command than Jackson, walking 1.9 batters per nine innings in his career versus 3.5.

Even though Haren landed on the disabled list in July for a bad back while with the Los Angeles Angels of Anaheim, he still made his final 13 starts of the season with a 3.58 ERA. He has started at least 30 games each of the past eight seasons, and from 2005 to 2010, he averaged 226 innings with a 3.49 ERA. He lost some velocity last season and had his worst campaign since 2004, but if he proves to be healthy, Haren is a short-term, lower-risk gamble with a proven track record. 

Haren also has postseason experience, making two starts for the Oakland Athletics in 2006 and five relief appearances for the St. Louis Cardinals during their World Series run in 2004. 

>>> Who will play first base? The Nationals still want Adam LaRoche. General Manager Mike Rizzo reported nothing new between the sides on Monday and that he wouldn’t pressure LaRoche into making a decision immediately. A quicker resolution to negotiations, however, would help shape the rest of the offseason.

The Nationals have held firm on offering only a two-year deal to LaRoche and the first baseman is seeking the job security of a three-year deal. LaRoche, however, has often talked about how much he and his family liked Washington, his teammates and the chance to win.

If the Nationals were to sign LaRoche, Michael Morse is the most likely trade chip. Before the Haren agreement, there was a sense that Morse could serve as a piece of a trade, possibly packaged with another player, for a starting pitcher. Right-hander James Shields of the Tampa Bay Rays, a team in need of power hitters, was a popular name. But now, with the starting rotation set, if Morse were to be traded, it may make more sense for the Nationals to seek relief help in return. Or, they could seek prospects, maybe even starting pitchers since the higher rungs of their minor league system are relatively slim on major league-ready starters.

Obviously, a difficult decision and negotiations lie ahead for the Nationals — but again, they’ve positioned themselves to have options. Morse at first? LaRoche at first? Tyler Moore at first, if they lose LaRoche and trade Morse? 

>>> Bolstering the Nationals bullpen: On Monday, the Nationals re-signed left-hander Zach Duke, who will serve as their left-handed long reliever and add starting pitching depth. Rizzo said ideally he would like to add a second left-hander to the bullpen, as Duke is the lone one as of now.

With Christian Garcia competing for a starting job in spring training, Henry Rodriguez returning from an elbow injury and uncertainty whether Sean Burnett, Michael Gonzalez and Tom Gorzelanny will return, the Nationals will look to bolster their bullpen with an arm.