The Argentine midfielder was forced to miss Saturday's 1-1 draw with Fulham due to a hamstring problem.
"It is possible Yacob will be available to play against United," Mel told the club's official website. "He is a very important player for us in the middle. He is strong and is playing well.
"It is important for us to play with three midfielders because now for us it is better."
West Brom are not in action this weekend due to scheduled opponents Sunderland's participation in the League Cup final.