At one time it appeared unimaginable that Messi could leave La Liga giants Barcelona, but the future of the Argentina international has been a hot topic in recent weeks amid rumours he is unhappy with life under head coach Luis Enrique.
Messi added further fuel to the fire when he stated at the FIFA Ballon d'Or awards "I don't know where I'll be next year", having previously suggested he had no desire to leave Camp Nou.
Real are considered one of the few teams with the financial capability to meet Messi's release clause.
Head coach Ancelotti stated it would be great for him to have Messi and Ballon d'Or winner Ronaldo together at the Santiago Bernabeu, although the Italian conceded the possibility is unlikely.
When asked if he could imagine both men in his team, he said: "I think so. But you have to remember that Cristiano is the standard bearer for Real Madrid, like Messi is for Barcelona.
"Both of them have their own team and their own history. Having both on the same side would be wonderful for us but it's difficult to see that ever happening."
Ancelotti also reiterated that there is no trouble regarding Ronaldo's relationship with team-mate Gareth Bale.
Ronaldo was visibly frustrated when the Welshman failed to tee him up for a goal in the second half of last Saturday's 3-0 victory over Espanyol, with supporters subsequently jeering Bale.
"They have a great relationship," Ancelotti added. "Yesterday, Cristiano asked to take a photo of all of us together including the staff to celebrate his Ballon d’Or. We celebrated together and that's that."
Ancelotti was speaking ahead of Real's Copa del Rey second-leg tie with rivals Atletico Madrid at the Bernabeu on Thursday.
Real trail 2-0 from last Wednesday's initial encounter and Ancelotti is well aware his team must play with a high intensity to turn around the deficit.
"We know Atletico well and we know how to play against them," he said. "We must put in an intense game but keep a cool head.
"You need intensity to your game when you play against Atletico because they have one of the most well-organised defences in Europe and it is always difficult to create openings against them."
