Lallan will not travel to Vicarage Road due to a slight knock as his side aim to maintain the unbeaten start to the Premier League.
Henderson, however, is available after returning to Melwood early from international duty with England after a hamstring complaint.
“[Jordan] is ready to play, that is all. At the moment it looks like we have pretty much a full squad – [although] there are the long-term injuries, of course,” said Klopp.
“Adam Lallana has a minor thing that makes him unavailable for the weekend, but all the rest came back healthy from the internationals, which is brilliant. So, we have to make a few decisions,” he added.
