It looks like the Nationals could start the season without their first baseman at 100% as they have learned that Adam LaRoche has a slight tear in his rotator cuff, according to Bill Ladson of MLB.com:
#Nats 1b Adam LaRoche has a slight tear in his rotator cuff. I'll have more on MLB.com.
Although it doesn't seem like the injury isn't serious enough to sideline LaRoche for a significant amount of time, it could limit him as far as his productivity is concerned. He is someone who relies on his left handed power swing, so this could affect his numbers int he early going for the Nats.
LaRoche was acquired this past offseason to fill some of the offensive void left behind by the departure of Adam Dunn.
LaRoche hit .261 with 25 homeruns and 100 RBI for the Arizona Diamonbacks last year.