Who's the Nationals' X factor for next season?

Grant Paulsen has to be the hardest-working guy at SiriusXM Radio. When I toted my Thai takeout in from the car Friday night, he was tag-teaming with Mel Antonen on the evening show on MLB Network Radio. When I get in the car after my Saturday morning Old Bagel and turn on the satellite radio, Paulsen is there again, breaking news of the Shin-Soo Choo signing by the Rangers. He's back on this morning on "Minors and Majors," the weekly show on the minor leagues. Does the guy ever sleep? Between nuggets about Choo's megadeal with Texas, Paulsen - who I first remember as a pre-teen, milling about the press box at Camden Yards - was asking listeners to name their favorite team's X factor for the 2014 season. In other words, what variable during the upcoming campaign could have the most significant impact on a team's chances? Since imitation is the sincerest form of flattery (and since I've given Paulsen full credit for the idea), I thought that would be an interesting question to pose to Nationals fans. What's the X factor for the Nats in 2014, and why? You can leave your thoughts in the comments section, but remember to explain the reasoning behind your choice. The Nats are an interesting team for this exercise in forward-thinking evaluation of a season that hasn't yet begun to play out. After last season's furious rush fell short of then-manager Davey Johnson's "World Series or bust" preseason proclamation, there are significant new pieces in place on South Capitol Street and numerous players who know they will be performing under a microscope. For example, maybe you think how new manager Matt Williams performs in his first go-around as a major league skipper will be the deciding factor on how the Nats finish. As I've previously written, Williams is pretty much a blank slate, and aside from his promise of some changes in the Nats' spring training regimen and his addition of a new coach responsible for defensive positioning based on advanced metrics, we don't know a lot about his managerial style. Left fielder Bryce Harper missed significant time with injuries last season, and wasn't able to replicate the impact of his Rookie of the Year campaign in 2012, so he's an X-factor candidate. So is third baseman Ryan Zimmerman, who rounded into defensive shape as last season wore on. He's battled injuries and inconsistency, and his average has dropped for three consecutive seasons. The 2013 version of first baseman Adam LaRoche was far different from the 2012 vintage - more at bat, but also in the field. How will shortstop Ian Desmond react in 2014? Will he continue to cement his role as the clubhouse conscience and steady on-field performance, or will talk of a well-deserved contract extension be a distraction? The same question about a long-term deal could be posed to right-hander Jordan Zimmermann, who is coming off his best season and is in line for a huge payday. Will newly acquired starting pitcher Doug Fister's groundball tendencies benefit from strong infield defense, further lowering his ERA? In the bullpen, can right-hander Drew Storen be more of the pitcher we saw after his mechanics were fine-tuned at Triple-A in August, and can rubber-armed Tyler Clippard, with four consecutive seasons of 70 or more appearances, maintain such a workload? Since I've posed the question (well, with Paulsen getting credit for the idea), it's only fair to share my X-factor National. That would be right-hander Stephen Strasburg, whose 8-9 record in 2012 has to improve in order for the Nationals to reclaim the National League East crown and a playoff berth. Some of Strasburg's other numbers - his 30 starts, 3.00 ERA, 1.049 WHIP and 191 strikeouts in 183 innings - are what you'd expect of a staff ace. But you don't need advanced metrics to tell you that the Nationals need to score more runs for the guy who is potentially their most dominating starter. I think the Nationals go as Strasburg goes in 2014. Who's your X factor National and why?