Thomas Tuchel expects Marc Bartra to be out for up to four weeks with a wrist injury suffered during the bomb attack which targeted Borussia Dortmund's team bus on Tuesday.
The Dortmund squad were on their way to Signal Iduna Park for the Champions League quarter-final clash against Monaco when three explosions went off near their coach.
Bartra was the only player to suffer a significant injury and underwent surgery on a fractured wrist on Tuesday night while bits of debris were also dislodged from the defender's hand as a result of the blasts.
Monaco went on to win the rearranged first-leg encounter 3-2 on Wednesday - less than 24 hours after the attack - in a breathless encounter in north-west Germany.
But Tuchel says the result was put into perspective by the "shock" of Tuesday evening's events and the ongoing attempt to quantify what had happened.
Speaking in a press conference, Tuchel said: "Compared to what happened on Tuesday, the importance of the game is zero.
"Each person concerned must deal with this situation differently. Some players only really realised the shock and the situation when they rejoined their families at home.
"We must find a way to get clear but we don't know yet how it's going to happen. It's incredibly hard to talk about. We can share only with each other and understand."
On Bartra's injury, Tuchel added: "It's a four-week break. He would like to play now."
Manchester City manager Pep Guardiola, who coached Bartra at Barcelona, passed on his best wishes to the 26-year-old.
"I wish him the best recovery possible," said Guardiola. "Fortunately it wasn't that serious but the world is getting crazy and we don't know what it goes to (next)."
Liverpool manager Jurgen Klopp admits he was scared for his former Dortmund players.
Klopp, who spent seven years at the Bundesliga club and signed many of the players who are still there, said: "Everyone can imagine it was a really difficult moment for me.
"I tried immediately to get some information. I was really concerned, scared for them (the players), I was scared for everyone."
In the first half on Wednesday it appeared the events had taken their toll as Monaco surged into a two-goal lead through Kylian Mbappe's opener and a Sven Bender own goal.
The second half was a different story as Ousmane Dembele and Shinji Kagawa scored either side of Mbappe's second to give the German side hope for the return leg.
Dortmund midfielder Nuri Sahin admitted football was far from his mind, particularly in the opening 45 minutes.
He said on Scandinavian TV: "I don't know if people can understand this, but until I was on the pitch in the second half I did not think about football to be honest.
"I know football is very important, we love football, we suffer with football and I know we earn a lot of money and have a privileged life but we are human beings. There is so much more than football in this world. (On Tuesday) night we felt it."
Team-mate Julian Weigl added on the club website: "At the start of the match you could see the events were hanging over us.
"There were no other alternatives than to play. But it was really difficult for us. I think the majority of us didn't get much sleep, myself included."
Tuchel now has to prepare his side to face Eintracht Frankfurt in the Bundesliga this weekend.
"Yesterday we showed a great performance with lots of courage," added Tuchel. "On Saturday we try again. You're the best athlete if you're not worried."
Tuchel claimed in the aftermath of Wednesday's match that his side were told they had to play by a text message from Uefa.
However, the governing body issued a statement saying the Bundesliga club agreed to the rearrangement of the game.
It is understood Uefa president Aleksander Ceferin made it clear no one should play if they did not want to and that there were five Dortmund representatives at the discussions with the governing body.
An Iraqi national, a suspected member of the Islamic State group, has been arrested over the bomb attack, according to German prosecutors.
But prosecutors say they have so far found no evidence to link the 26-year-old, whom they allege led a 10-strong unit which prepared abductions, extortions and killings in Iraq, to Tuesday night's attack.
They have requested an arrest warrant to be able to hold the man, named only as Abdul Beset A, over his Islamic State links. They say he travelled to Turkey in March 2015 and Germany early the following year.
A statement from the German Federal Prosecutor's Office said: "The accused is strongly suspected of being involved in Iraq as a member of the foreign terrorist group 'Islamic State' (IS).
"The accused was arrested (on Wednesday) in connection with the attack on the Borussia Dortmund team coach. The investigations have so far shown no evidence that the accused participated in the attack."
Additional reporting by the Press Association.