It turns out that Herrera did not have the right to declare free agency once he passed through waivers.
The Mets are concerned Herrera's effectiveness will decrease as NL East batters become more familiar with his screwball.
They privately cite Herrera's numbers swooning against NL Central teams, who were familiar with him because of his longtime association with the Cincinnati Reds.
Daniel Herrera's Stats
|2011 Regular Season||18||0||0||0||9.2||13||6||5||1||3||5||0||1||0||1||0||1.66||4.66|