Livan 5.29 4.79
Batista 5.28 5.18
On the basis of their projections, Batista looks the weakest candidate. Livan's FIP (Fielding Independent Pitching, which just counts home runs, walks and strikeouts) puts him ahead of Balester, JD Martin and Olsen(!), but his ERA is the worst of everyone's.
I actually came to write a post about rotation candidates with options still available, and the Livan news ensures that I get a longer post than I had planned.
The simple fact is most of our rotation candidates still have options. We can be confident that Lannan and Marquis are set. Olsen seems to be 'a lock' according to Mr Riggleman. The people who fill out the last two spots will presumably be those who do well in spring training, with one caveat — if they are out of options, they have to clear waivers to make it down to the minors.
This may affect two pitchers. One, I'm sure of: Matt Chico is out of options. I also think he's potentially good enough to draw a waiver claim. The other — JD Martin — might have option problems. The option rules are a bit complicated, given the kind of data one can access easily. Martin appears to have been a six-year free agent, so if he's been on a 40-man roster any length of time he can easily have used up his options.
As a consequence, I'm designating Chico as the likely #4 starter. He could get a bullpen role, but there's actually a logjam there. That's a story for another time.
6 March 2010 EDIT: Brian @ Nationals Farm Authority has a full options run-down here. Seems JD Martin still has all his options left.