Our captain was sent off for two yellow cards in the entertaining 3-3 draw at FC Porto, last time out in the competition, and serves a one-game ban.
Bruno's absence opens up the question as to who will replace him in the no.10 role, as Erik ten Hag considers his options for Thursday's 20:00 BST kick-off.
There are existing issues to contend with in midfield as Kobbie Mainoo, Mason Mount, Toby Collyer and Dan Gore were all unavailable for the victory over Brentford.
However, Manuel Ugarte came off the bench at the weekend and, hopefully, Casemiro will be okay, after appearing to pick up a knock in the closing stages of the 2-1 triumph.