Juve have been challenged by the player's agent to meet his contract's buyout clause.
Allegri responded: "About [Wesley] Sneijder, let's see if he comes before speculating on where he'll play. For the moment he's still a player with Galatasaray.
"The objective for Juventus has to be that of improving the team. And to improve on the technical level we must get players who are, qualitatively speaking, at the same level as those we already have, or even better.
"I think this team has the possibility of improving, regardless of the characteristics of the players. Sneijder of course has some great technical qualities and he's proven that over his career.
"He'd be completing a strong midfield, which would also create competition in that department, and that's important.
"January is a strange market. We have to be realistic and see which players we can get, and some of those can't play in the Champions League.
"That's not to say the Champions League is a secondary goal, because it's a primary goal.
"When we prepare to face Borussia Dortmund we're not doing it just to play two games, but to progress, because I think this team has the ability to progress in the Champions League.
"We're convinced of that, because we showed it in the group stage."