The 32-year-old is likely to be out for four weeks after suffering bruising to his eye following a collision with Gloucester full-back Charlie Sharples in the 18-3 defeat on Friday night.
“Lewis took a serious knock at the weekend, which is obviously very tough on him. He was just getting used to the Bath style of play, and it’s equally frustrating for the rest of us to lose him at this stage in the season.
“We will of course make sure he receives the best possible attention to get him back on the field as, and when, he’s ready.”
Coach Martin Johnson gave Moody the nod to replace Steve Borthwick as captain for the summer tour of Australia after the Saracens lock suffered a knee injury.
He led the side to a memorable 21-20 victory over the Wallabies in Sydney and was expected to keep the captaincy for the four-match series against New Zealand, Australia, Samoa and world champions South Africa this autumn.
His absence though would leave Johnson short of candidates to take the captain’s armband for the first game against the All Blacks on 6 November.
Centre Mike Tindall, fly-half Jonny Wilkinson and No8 Nick Easter are among the leading candidates with Borthwick left out of the elite 32.