The explicit statement that is best supported by the details in the passage is:
Mr. Rogers wants another candidate because Mr. Herrman has lost too much weight.
This is clearly indicated in Mr. Rogers' speech where he mentions that Mr. Herrman has "lost more flesh during the week that we have lain here than any among us" and suggests replacing him with Mr. Lucius Harris, who is "well and honorably known to us all." This statement directly ties Mr. Rogers’ reasoning to Mr. Herrman’s physical condition.