Bobby Parnell will replace Mejia in the bullpen. He’s been pitching fairly well at Triple-A Buffalo where he’s 1-1 with a 4.14 ERA in 41.1 IP. He pitched in 68 games including 8 starts for the awful 2009 Mets to a 5.30 ERA.
I’m still not sure that I see Mejia as a starter. He’s clearly still a “thrower” not a pitcher. But the velocity that he generates and the lack of secondary pitches seems to me would be more of a fit in the bullpen than the rotation. Either way, he’s not developed enough to succeed in the majors in either capacity right now.