Which SP to pick up?

[StckFigure]

I'm being offered a trade of Heath Bell + starter for Chris Carpenter. I've had excellent starting pitching (5x5 NL roto league) so far, but come back down to earth somewhat, so what used to be a big lead in ERA and WHIP is now a much tighter race. My only closer is John Axford, and I'm somewhere around 7th place (out of 10) in saves. The potential trader would include one (possibly two) of the following starters in the deal: Randy Wells, James McDonald, Javier Vazquez, and Tim Stauffer. Obviously none of these are close to Carpenter's potential, but he's underperforming a bit. Are any of these suitable replacements worth picking up Bell for? Alternatively, his other closer is Salas, whom he values slightly less, but who might be a better pickup for me given trade rumors around Bell... so thoughts on that are also appreciated. My starting staff currently is Carpenter, Kyle Lohse, Travis Wood, Paul Maholm, Jhoulys Chacin, and Chris Narveson, and I have Josh Johnson on the DL, so there is still some strength there, though I've traded away some pitching to improve my offense recently.

As an alternative option, would one of my existing SPs other than Carpenter be a better trade for Salas or Bell, straight up?

Thank you!

[ahcryky]

Carpenter has pitched a lot better in his last four starts. There aren't any pitchers in that scenario that I would want. If you could get Salas of the relievers for Narverson or Maholm I would do it..... Doubt you could get Bell. I don't see your staff as being able to take the hit of losing Carpenter.