05 was likely Carpenter's career year. He will still be a good pitcher but IMO highly unlikely to repeat 05. My guess is he will produce somewhere between 04 and 05. Blalock returns to his 03, 04 level which is more likely than not, then he and Carpenter will virtually be a wash.
Given the upside of Schmidt, the probability that Schmdit AND Blalock will outproduce Carpenter and a replacement 3B is greater than not. The reward is certainly worth the risk.
"Think of how stupid the average person is, and realize half of them are stupider than that." ~George Carlin