I missed this somehow. The Marlins have added two players into the mix, according to the Baseball America Minor League Transaction Blog.
Signed: RHP Doug Waechter, LHP Carlos Alvarez
Doug Waechter started against the Marlins in 2006 when he was with the Rays. He didn't get the win but pitched reasonably well in the game.
I don't know much about Carlos Alvarez other than he was in Dodgers organization and isn't a very big guy in stature.
I'm sure both signed minor league contracts.