Salzburg boss Marco Rose offered his support to Leigh Griffiths after the Celtic striker dropped out of football for personal reasons ahead of the Europa League encounter at Parkhead tonight.
Hoops manager Brendan Rodgers revealed at his pre-match press conference at Lennoxtown that the 28-year-old Scotland international will be out "for a period of time" as he "needs some help".
Speaking before his side trained at Celtic Park in preparation for the final Group B encounter, Rose said: "That is news to me. Sorry to hear that. He is a good player.
"It just shows you that there are more important things than the business, it shows that you are dealing with humans, so I wish him all the best and hopefully he comes back just as strong or even stronger. I have experienced things like this too, it is not just a problem in football but in all of society.
"We wish him the best and the only thing you can do in this case is support him."
Rose insists Celtic will have to earn the point they require to ensure they join Salzburg in the knockout stages.
The Austrian side have won all five Group B matches, including a 3-1 home win over the Hoops in October, and are already qualified as section winners.
Rose said: "Obviously Celtic will have more supporters than the last game in Salzburg but that is what we are looking forward to, the atmosphere.
"It is clear that Celtic need a point but we want to play a good game, so Celtic have to earn that point because we will give everything.
"We have reached our most important goal already, we have advanced to the knockout stages.
"We are in first place but it is not all about winning six games, we want to be part of a great game.
"I think everyone who comes here have earned that right to experience a great game.
"It is a very cool stadium, you can feel the atmosphere even without the supporters. Even in the locker rooms you can breathe in the atmosphere.
"The supporters are notorious, amazing. We are happy to be here, but we also want to show that we are rightfully here."
Goalkeeper Alexander Walke is looking forward to a European night at Celtic Park.
The 35-year-old German said: "It is very special to play here.
"I can go as far as to say it is a little dream of mine to play here and I am looking forward (to it) a lot."