Where are the weaknesses?

Another day has passed, and still no announcement from the Red Sox on whether they've finally completed their deal with first baseman/catcher Mike Napoli. Napoli and the Red Sox agreed to terms on a three-year, $39 million deal at the Winter Meetings more than two weeks ago, but the deal has still not been made official. There are reports that the Red Sox have found some sort of issues with Napoli's physical, and while the two sides are still working on a way to finalize the contract they have in place, Boston continues to lurk as a possible landing spot for Adam LaRoche if the Napoli deal falls through. The Orioles, another team in need of a power-hitting first baseman, are interested in LaRoche, but the Baltimore Sun reports that they're scared off by the fact that signing LaRoche would cause them to lose their first-round pick in the 2013 First-Year Player Draft. Because the Nationals extended LaRoche a qualifying offer (which he subsequently declined), they would receive a compensatory draft pick if LaRoche signs elsewhere. The team signing LaRoche would need to forfeit a pick, something most teams are hesitant to do these days, given the emphasis today's executives put on drafting and developing prospects. That could very well be a major factor in LaRoche's lack of big-money offers this offseason. For the sake of discussion, let's assume LaRoche ends up deciding not to re-sign with the Nationals, leaving the 2013 roster as it's currently constructed. If the Nats go into the season with their roster as is, where are the areas of weakness on this team? One, for sure, would be the left-handed options (or lack thereof) out of the bullpen. Currently, Zach Duke is the only lefty reliever on the 40-man roster, and while he did a nice job working up to the majors last season after spending much of the year at Triple-A Syracuse, if he's the only southpaw Davey Johnson can turn to in relief, the Nats might be in trouble. General manager Mike Rizzo is looking for another lefty reliever (J.P. Howell remains a name to watch), Bill Bray is an option after being signed to a minor league deal, and the Nats have some righties in the 'pen who have posted quality numbers against left-handed hitters. But Duke has allowed lefties to hit .279 off him for his career. The Nats need help there. Another weakness you could point to if LaRoche doesn't return is the lefty/righty balance in the Nationals' lineup. One thing Johnson loved about his 2012 lineup was that it featured a nice mix of offensive threats from both sides of the plate. He could split up the right-handed bats in his order with LaRoche and Bryce Harper, making it tough for opposing managers to pick relievers to attack Nats hitters in the late innings. If LaRoche signs elsewhere, Michael Morse or Tyler Moore will be playing first base, leaving the Nats with Harper and Denard Span as the left-handed hitters in their lineup, and one switch hitter in Danny Espinosa. That's not awful, but it wouldn't give the Nats nearly as much pop from the left side as they had last year. Some fans might claim that second base is a weakness, if Espinosa indeed remains the everyday guy at that spot. Espinosa led the league in strikeouts last season, had a .315 on-base percentage and at times struggled to make productive outs. He did hit 17 home runs and play an excellent defensive second base, however. Espinosa is clearly a work in progress, but the Nats are looking for him to take a step forward this season. What are the weaknesses you see with this roster? Anything outside of the areas I addressed?