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Is it realistic to think anyone could afford to buy Lionel Messi from Barcelona?

Only two clubs could buy Lionel Messi outright and satisfy Financial Fair Play, according to a finance expert.

And Real Madrid and Manchester United would struggle to pay Messi's wages without breaking Uefa's rules.

The rest of Europe's elite would have to stagger a payment over a number of years to meet the £170m valuation.

"With the revenue they generate and cash reserves, only United and Real Madrid could pay the fee," said Rob Wilson external-link of Sheffield Hallam University.

"With salary costs probably even they couldn't stay within FFP."

World's most valuable players 220m Euros (£172.43m) Lionel Messi (Barcelona) 133m Euros (£104.24m) Cristiano Ronaldo (Real Madrid) 99m Euros (£77.60m) Eden Hazard (Chelsea) 84m Euros (£65.84m) Diego Costa (Chelsea) 72m Euros (£56.43m) Paul Pogba (Juventus) 65m Euros (£50.95m) Sergio Aguero (Manchester City) Source: CIES Football Observatory (January, 2015)

Messi's contract does not expire until 2019 and Wilson said it would be unlikely that Barcelona would accept a staggered transfer payment.

"Unless Messi absolutely wanted to get out of the club, why would Barcelona agree to that?

"Staggering the payments would certainly make it easier for Chelsea, Manchester City, PSG and Bayern Munich but Manchester United demanded the fee up front when they sold Cristiano Ronaldo and I strongly suspect it would be the same for Messi," Wilson said.

There is no suggestion Real Madrid are interested in replicating the controversy created by their decision to sign Luis Figo from Barcelona in 2000.

But Messi, 27, has been the subject of increasing speculation.

He was left out of the Barcelona starting line-up for the defeat at Real Sociedad, subsequently began following Chelsea on Instagram and his future was the subject of a vague comment external-link by coach Luis Enrique.

Yet the days when clubs merely had to decide whether they could afford a financial package for a player are over.

World's richest clubs (turnover) £444.7m - Real Madrid £271m - Manchester City £413.6m - Barcelona £260m - Chelsea £369.6m - Bayern Munich £243.6m - Arsenal £363.2m - Manchester United £233.5m - Juventus £341.8m - Paris St Germain £225.8m - AC Milan Source: Deloitte Football Money League (January, 2014)

Now, under FFP, if they exceed losses of 30m Euros (£23.5m) over a three-year period that includes the present campaign, they are liable to be sanctioned by Uefa.

That figure is a reduction on the £45m over three years that was in operation until last season, and which Manchester City and Paris St-Germain were fined £49m for breaching last term.

It means unless clubs took the radical step of selling a number of senior players to fund a single purchase, their only other option would be to push through the transfer and deal with the fall-out when it happened, a stance Wilson believes could prove very costly.

"Chelsea and Manchester City clearly have the financial power but whether they would just do the deal and worry about the consequences afterwards is another matter," said Wilson.

"Most people thought Uefa would take a light touch approach to FFP. In fact they have shown a willingness to apply it pretty rigorously."

Lionel Messi scoring in the 2009 Champions League final against Manchester United

Messi after Argentina's World Cup final defeat by Germany last year