There have been calls for De Gea to be dropped after his errors cost United in Sunday's FA Cup semi-final loss to Chelsea.
Asked if he could confirm the Spaniard would start at Old Trafford, Solskjaer replied: "I don't want to talk about it. We stick together as a group.
"We're going to stick together as a group and as I said he's proven before he's mentally strong. We'll stay together and we'll see the team on Wednesday night."
Asked about his whole team selection, Solskjaer added: "You have to [make big calls], every position is a big one here so you've got to do what is right for the team and the club," Solskjaer said. "We'll do that on Wednesday, we'll do that on Sunday and then when the season's finished we'll make more decisions."