But the New Zealand hooker is back to lead the Gwent region for their European opener in Pool 5.
Willis said: "It's great to be back for arguably the finest rugby tournament around and one in which we truly will be tested by some of the finest teams in Europe.
"We've got a very challenging pool but our preparation has been good and has put an extra spring in the lads step and brought an extra edge to training.
"It was great last week for the team to grind out another win and continue to build the momentum we've gained so far."
Wales prop Rhys Thomas, lock Luke Charteris and fly-half James Arlidge also return for the clash at Rodney Parade.
Newport Gwent Dragons: Forwards: Steve Jones, Aaron Coundley, Andrew Hall, Adam Jones, Joe Bearman, Rhys Thomas, Lewis Evans, Luke Charteris, Colin Charvis, Adam Black, Tom Willis (captain), Grant Webb, Dan Lydiate, Ricahrd Parks, Jamie Ringer.
Backs: Gareth Wyatt, Phillip Dollman, Wayne Evans, Marc Stcherbina, Robert Lewis, Rory Sidey, Richard Fussell, Jason Tovey, Shaun Connor, James Arlidge, Ashley Smith, Rhodri Gomer Davies, Tal Selley.