Will Carroll at Baseball Prospectus produces an analysis each year that projects the injury risk of every major league regular. Carroll factors in past injury history, position, pitcher usage, age, and other variables that correlate with increased injury risk. He categorizes players as green lights, yellow lights, and red lights based on the degree of injury risk.
Last year, Carroll had the Nationals as one of the most injury-prone teams in baseball, with 6 "reds" in the starting lineup (Lo Duca, Johnson, Patterson, Hill, Guzman, Bergmann), 2 backed up by reds (Fatsrada and Da Meat). (Sorry Jim, it wasn't just bad luck.)
Carroll just posted this year's team health reports, and the Nationals again have 6 reds in their starting lineup. Nick Johnson, Shawn Hill, Jesus Flores, Josh Willingham, Austin Kearns, and Daniel Cabrera all rate as high injury risks. Only the Dodgers, Mariners, Mets, and Red Sox have more high risk players in key roles.
The Nationals have five "greens"--Anderson Hernandez, Lastings Milledge, Scott Olsen, Collin Balester and Cristian Guzman. (I'm frankly incredulous at the idea that Guzman is a green. That guy should be working on four straight seasons with a DL appearance, except Jim carried him for two weeks on the active roster when he was unavailable last year. But whatever.)
I'm also surprised that Elijah Dukes only rates as a yellow, though I hope Will's relative optimism is justified. Saul Rivera is another suspicious yellow. Given the number of innings he's thrown the last couple years, he has to be very close to being a red.