Messi, 35, is out of contract with PSG at the end of the season and Barca vice president Eduard Romeu said last week it would be viable to bring him back to the club on a financial level.
Romeu's remarks came after president Joan Laporta opened the door to a sensational reunion with Messi in an interview with ESPN in the summer.
"With Leo, let's see, but it's not the moment to talk about it right now," Xavi said in a news conference ahead of Barca's Champions League game against Internazionale on Tuesday.
"You know the love I have for him. He is a friend and I will always wish him the best. Barca is his home, but we're not doing him any favours speaking about [his future], either.
"Let's leave him in peace to enjoy his time in Paris and wish him all the best."
Talk of Messi's return comes as Barca finally appear to have turned the page on the Argentina forward, with Robert Lewandowski's goal in the weekend's win over Mallorca taking them to the top of LaLiga for the first time in over two years.
However, while they remain unbeaten domestically, Barca still have work to do to avoid being knocked out of the Champions League group stage for the second season running.
After Barca and Inter both lost to Bayern Munich, it looks like the upcoming meetings between the two sides -- at San Siro on Tuesday and Camp Nou next week -- will decide who advances with the German champions.
"It seems like that's the case," Xavi said when asked if Barca and Inter were now playing for second place. "We both lost to Bayern and beat Viktoria [Plzen], so Tuesday is a very important game -- and the one next week as well at home.
"Let's see how Bayern do on Tuesday [against Plzen], but we can't fail. We are in good form, but we have to keep demonstrating that. We have already let Bayern off in this competition. We have to match the way we played in Munich, but this time get the result.
"It's a confidence boost to be top of LaLiga, it shows we are doing things well, but Tuesday is another story. We didn't get any points in Munich so it's time to show we can compete in this competition. It's a huge game."
Both sides have injury problems going into the game. Barca are once again without Jules Kounde, Hector Bellerin, Ronald Araujo, Frenkie de Jong and Memphis Depay. Inter, meanwhile, will be missing Romelu Lukaku and Marcelo Brozovic, while a late decision will be made on Lautaro Martinez.
In addition to injury problems, Inter go into Tuesday's game on the back of a defeat to Roma, their fourth in eight Serie A games already this season.
"That is not significant, it's still Inter," Xavi added, playing down concerns about the Italian side's form. "They're a strong team. They have a different system to what we have faced so far, a really strong spine and a good coach [in Simone Inzaghi]. They are really tough opponents."