The Scottish champions were already without the services of suspended midfield duo Stefan Johansen and Nir Bitton for the pivotal Group A clash with Ajax at Celtic Park, while playmaker Kris Commons is unlikely to recover from a hamstring problem in time.
The major setback for Brown, who will be sidelined for eight to 12 weeks with a knee ligament injury suffered in Saturday’s 0-0 draw against Kilmarnock, has further complicated Celtic manager Deila’s selection problems.
Charlie Mulgrew, who has been absent for the past two months with a thigh injury, is back in full training and is included in the squad tonight.
But Deila is wary of throwing the experienced Scotland international straight back into the starting line-up.
As he considers his options, the Norwegian coach will also assess the claims of striker Stokes and midfielder Allan for a match in which only a victory will keep Celtic’s qualification fate in their own hands going into their final group fixture against Fenerbahce in Istanbul on 10 December.
Stokes has been almost completely frozen out of the first-team picture this season, making his only start and last appearance back in August.
Allan, whose signing from Hibs generated so much publicity after Rangers’ lengthy pursuit of him, has managed just three substitute appearances for Deila’s side so far.
“Stokesy is available, he is in my thoughts and in the squad,” said Deila. “Scott Allan has the level to come in and do it. He has shown that in training, he has done well.
“But, of course, to put all the responsibility in his hands is not right.
“We need to do this as a team, go for it on Thursday night and really show we are one team, one unit. We need to be very, very aggressive and put a lot of energy into the game.
“Charlie is available, so we’ll see with him. He has had just one week of football training, but has ran a lot.
“Of course, it is not an ideal scenario to have a player who has been out for two or three months, but he’s in the squad and can also be available from the bench.
“When Charlie is in his best shape, he’s an outstanding midfielder. We’ll use the team we feel is the best for the game.”
Deila, who could also turn to Efe Ambrose for one of the holding midfield positions, remained philosophical amid his disappointment at the loss of influential captain Brown.
“What can you do about it?” shrugged Deila. “We work hard and honestly every day and try to improve things. These injuries are just very unlucky but every team has them. I’m very unhappy for Broony because he had just come back again and wanted to play. He is an important player and was in good shape.
“For ourselves, it is a blow. But it is nothing to be sad about. You just have to keep on working. There are a lot of players who have worked hard all season who will get a new chance now.”
Deila also revealed his January transfer window shopping list will now focus on the search for more experienced players to help mentor and develop the younger members of his squad.
“It’s now very important we look for that kind of player in January,” he said. “We have a lot of talent, but you need leaders or parents to these players to get them to grow. I would rather have one or two players that can stretch the level and have experience, than have five youngsters who are talented players because you can’t get through all the ties with them. Ryan Christie is coming, Scott Allan, Callum McGregor and Aidan Nesbitt are all younger too – you need leaders around these young boys to get the best of out of them.
“We know what kind of budget we have. It is possible. We have to look at players who are important in their teams and not in the biggest leagues. You don’t get a guy from the English Premier League who is playing week in, week out. We also get players who are in their way not good enough for that level, but who want to have a different challenge.”