I think he is implying that neither is a great pitcher anyway..
This. Neither one is high on my list as a future closer. I liked Rosenthal but he has shown nothing at this point that would make me want to own him as a speculative add. Romo is pretty safe. When you speculate on future closers there is usually a decent chance they get the job sometime in the future. I just don't see it happening with out an injury like you said so why waste a roster spot on a guy that is unlikely to get a shot. Should be better players out there to own.