La Liga champions Barca have been linked to Neymar, who left Camp Nou for French giants PSG in a world-record €222 million ($250 million/£200 million) deal in 2017.
The situation was only exasperated in recent days as Neymar failed to turn up to the first day of pre-season training, causing PSG to vow to take action in response.
Neymar's father responded by saying that the club knew his son would miss out to attend a charity event, but PSG sporting director Leonardo confirmed Neymar is available for the right price.
Xavi played alongside Neymar for two seasons before moving to Qatari side Al Sadd in 2015 and the 39-year-old told Movistar: "He would be an incredible signing.
"But I see it as being difficult, honestly. I think it's very difficult.
"We have seen so many things that I thought I'd never see though, such as PSG paying €222 million, so we'll have to wait.
"There's no doubt that he's one of the best players in the world, but let's see what Barcelona do."
While Neymar's future is uncertain, Atletico Madrid star Antoine Griezmann is reportedly set to join Barca in the very near future.
France international and World Cup winner Griezmann – who has a €120 million ($135 million/£107 million) release clause – will leave Atletico after five years and Barca are favourites to sign the forward after missing out on his services last summer.
The signing would be a good one, according to former Barca midfielder Xavi, who believes he'd be a good fit at Camp Nou despite the delay in confirming a deal.
"He's a great player, a world star," Xavi added. "He made a difference with Atletico Madrid and with France. He's an extraordinary player.
"It's still not official, but it seems like he's going to Barcelona. I think it'll be a great signing."