With Ankiel now on the 40-man roster, the Nationals have 42 players on the list. So they'll need to take two players off of it in the near future.
Twenty-six of the 42 players on the roster are pitchers, and the most likely candidates to be designated for assignment are there. Reliever Atahualpa Severino is one name that sticks out as a possibility. The Nationals could also decide to bump one of their older starting prospects off the list, like Matt Chico or J.D. Martin.
Even if those players stay on the list, this is going to be an interesting year for them; Chico, Martin and Garrett Mock will have a tough time making the Nationals' rotation, and another crop of prospects from the Nationals' last two drafts will move through the minors this year. It's likely all three could be in Triple-A as pitching inventory or a possible injury replacement, but they'll find the climate to make the rotation much less favorable than in 2008 or 2009, when Chico and Mock in particular factored much more prominently in the Nationals' plans.
For now, the 40-man roster is two names too long, and we'll wait to see what the Nationals do.