Bernard is a centre-back who has previously spent time out on loan with Hull City and Salford City, and scored an own goal for United in their Europa League group stage clash with Kazakh side Astana three years ago.
Ten Hag is otherwise likely to name a strong lineup as the 52-year-old aims to compete for his first silverware with the club, with United not winning a trophy since their Europa League triumph in 2017.
“First of all, all the games that we play, we have only one aim,” said Ten Hag in a news conference. “We have to win, so that is the most important. We have to win, so we put the best players on the pitch we have. For every game, we make a proper plan for the line-up and tomorrow is the same.
“Of course, we have a lot of games to cover and this is a different competition. We plan some changes but want to play a strong team. We have only one aim. We have to win tomorrow, to go to the next round.