But the two players have things in common.
Both are South American, both are aged 27, both are internationals, both are clever players who love to take on defenders, both ply their trade in Europe and they are both trapped by the current transfer system.
It might seem weird to talk of Messi being trapped and any cage is certainly made of gold. The talk of him wanting to leave Barcelona is most probably just talk.
Yet his wages and his transfer value are now so huge he is effectively priced out of the market.
Financial Fair Play is structured so the individual sponsorship deal which has been rumoured would probably breach the regulations.
Sports lawyers argue a legal challenge might succeed, on the grounds of restraint of trade or a similar get out for players of exceptional value. Where that would leave FFP is anyone’s guess.
It is hard to get too worked up about Messi’s situation, Estigarribia is another matter.
The Paraguayan – usually known as Chelo – is one of that anonymous army of footballers whose “economic rights” are in the hands of an investment fund rather than a club.
A few past cases of third party ownership are well-known, along them Sergio Aguero and Radamel Falcao. Both of them have done well out of TPO. Many do not.
Unlike others Chelo has been prepared to go public about the effect TPO has had on his career.
He started out at Parguayan club Cerro Porteno and since 2011 has been nominally with Deportivo Maldonado in Uruguay, but in fact has played in France, Argentina and at four different Italian clubs.
First he was on loan at Juventus, part of their title-winning side, subsequently at Sampdoria, Chievo and Atalanta.
Each move has been dictated by a shadowy fund called General Soccer Management.
“GSM had previously sent me to France,” he says, “and they wanted €5 million to release me. Juventus would have kept me on but didn’t want to spend that sum.
“Then at Samp I played 34 out of 38 matches but I didn’t stay, for the same reason. And then again: Marcelo, we’d hold on to you, but...”
As Estigarribia explains, he signed up with GSM, who also act as his agent, when he was young and inexperienced: “I didn’t have a family at the time and I thought: if I’m here today and there tomorrow, what does it matter? I would a thousand times rather my registration now was with a club.”
The transfer window that opens in a month’s time will be the first since Fifa announced its decision to ban TPO worldwide. It will also be the last window before the new regulations on player agents – henceforth to be known as intermediaries – come into force.
The January window is often like one of those antiques programmes you can watch on daytime television. It looks like it might be interesting but in the end the apparent bargains are overpriced and late decisions turn out to be costly mistakes.
This time might be more lively, behind the scenes at least. It will be the last chance for agents to do deals before they lose their exclusive rights to represent players in April. It is also the last window of opportunity for deals at the current fee rates, which are often 5% or more.
After April there will be a 3% ceiling. So there might be some jockeying to cement longer-term contracts with players and possibly conclude certain deals in advance.
Will there also be a reaction from investment funds to the threatened ban on TPO?
All the signs are that they don’t believe it can be achieved, at least in the short-term, or that they think there are ways around it.
Doyen, the most prominent TPO operation, says there is up to €200 million at its disposal. Only a fortnight ago the company signed up a couple more young Brazilian players.
As with other issues, Fifa’s credibility is at an all-time low.