Moody, who has 63 caps for England, was handed the captaincy for the summer tour to Australia and guided Martin Johnson's men to a famous 21-20 victory.
Previous captain Steve Borthwick missed the Australia tour with a knee injury but has since been demoted to the second-string Saxons squad.
And Johnson looks set to be forced to name a new skipper for the visit of the All Blacks with Moody absent.
Bath coach Steve Meehan said: "Lewis took a serious knock. We'll make sure he receives the best attention to get him back on the field as and when he's ready."