However, international boss Age Hareides believes the Bees star, alongside Simon Kjær, fit the shape he wants to play.
And Christensen may have to look to play in midfield to get a run in the Denmark side.
Hareides told Danish outlet Ekstra Bladet ahead of the first leg: "Andreas Christensen has been doing great. There is no doubt about that.
"But no matter whether you play for Real Madrid, Barcelona or Chelsea, it is about what works best for the team and how you fit into it."
He added: "Bjellend and Kjær work well together. I feel that (Christensen) must fight to get into the national team in a different position in the future.
"I would like to see him play as a defensive midfielder, for instance."
Christensen was full of praise for the Brentford star and understood why the experienced defender was selected ahead of him.
“There is absolutely no reason to change that," he said before the game. "I am young, patient and will be able to break into the team in the future. The only thing I wish for is World Cup qualification."
He added: "(Bjellend) has more experience than me but I have more pace in my legs.
"We're both very calm with the ball and like to play it out from the back."
And the Chelsea man would also be open to play a bit further up the field.
"I see no problems in trying," he said. "It's been a while since I last played in that position so I would need time to get comfortable but I am ready for it."
Bjelland shone in the first leg and is set to keep his place for the trip to Dublin.