Soares has been in training with the first team for the past two weeks, playing an U23 game against Blackburn as well as a first team friendly with Southampton, while Cairney has been training with the side as he recovers from his knee problem.
While it still may be too early for the skipper to return, with the manager taking everything into account on whether he will be ready to play a part tomorrow, it looks likely that Soares will find a place in the squad now he is fully fit.
Meanwhile, Aboubakar Kamara will definitely miss the tie as he continues his recovery from injury that saw him limp off against Nottinham Forest before the international break, with the boss expecting him to return to training on Tuesday.
Jokanovic said: "He (Soares) is good, Rafa has been working with us for two weeks and the long period is behind him and he now has chance to compete.
"He is working hard and we believe in the future he can be useful for us.
"He could be in the squad for us tomorrow.
"Tom Cairney has completed part of the work with the squad this week, there are many positives around him and in the past he has had many ups and downs.
"In the beginning, he played only two games and we are going to try find the way to use him in the games in front of us, it is a little bit early to give you a final answer but entirely I am still deciding everything if he can be part of the squad for tomorrow's game too.
"We expect Kamara will be ready to start working with the group next Tuesday."