COMMENT: He has much to think about. But in the end, it'll be his decision. Diogo Costa and Manchester United. If Porto's young goalkeeper wants the move, United will make it happen...

But as we say, the 23 year-old will have a lot to think about. United have a plan in place, but it will require Costa's patience. And in the end, there's no guarantee he'll come out the other side triumphant.

With a €60m buyout clause there to be triggered, United have drawn up - at least on paper - the perfect succession plan. Dean Henderson was set to eventually inherit David de Gea's place as United's No1. But he talked himself out of that prospect at the start of the season. Martin Dubravka, meanwhile, will be returned to Newcastle United in June. The £6m option in his loan agreement dependent on appearances - which barring injury to De Gea - isn't going to happen.

So there's an opening for De Gea's long-term successor. And in Portugal, they're insisting John Murtough, United's football director, and manager Erik ten Hag have decided on Porto's 23 year-old keeper - voted the best in the country last season.

On paper, it appears perfect. Costa would arrive as competition for De Gea. To develop alongside the Spain international. Before, at the decent age of 25, eventually replacing him as the club's outright No1. But it'll mean one step back for two steps forward. The momentum he has built with Porto these past two years being put on hold as he takes on a new apprentice level position at Carrington. And at the end of it, there's still no certainty that De Gea's form will warrant moving him on.

It's a dilemma for Costa. Indeed, it's one for Portuguese football. For many inside the game over there, Costa could be the best they've seen this century. Aware of the growing interest in the youngster, Portuguese pundits have no doubt about the shot-stopper's potential.

"The best clubs will be on the lookout. I have no doubt, he will be one of the best in the world," says former Portugal international keeper Quim. "Wherever he goes he will be successful."

Former Porto keeper Jorge Amaral also insists, "(Costa) continues the tradition of other goalkeepers, such as Vítor Baia, who belong abroad. Sooner or later he will leave for one of the greats of world football.

"His performances have been fantastic. A great career was already expected, but with these performances, game after game, it won't be long until he leaves FC Porto."

Pedro Pereira, Porto's former goalkeeper coach, worked with Costa and addressed the United rumours directly: "It is normal for these clubs to look at him as a potential target. FC Porto is excellent in the way it manages its assets and, when the time comes for a possible transfer, it will know how to do it in the best way."

Indeed, you sense something is brewing regarding the United interest, with it emerging over the last 24 hours that Porto will push Costa to open new contract talks before the World Cup. With a deal to 2026, his €60m buyout clause does leave Porto vulnerable. "If he has a good World Cup that clause will look cheap," says Maniche, the former Chelsea and Porto midfielder.

And there is a clamour for Fernando Santos, the Portugal coach, to go with Costa ahead of AS Roma's Rui Patricio in Qatar. Despite his youth, many insist Costa could handle the spotlight. Pereira again, "If Fernando Santos chooses to use Diogo, he is ready to take on this challenge and be, potentially, decisive for Portugal."

So there's that momentum. That recognition. He's Portuguese football's latest shooting star. Is Costa really going to shelve all that for a bit-part role next season at Old Trafford?

United will be banking on he does. The scouting reports submitted have been glowing. Costa is everything Ten Hag wants in a goalkeeper. From his consistency and potential. To his passing game. If required, United are prepared to meet his €60m clause.

Of course, this was supposed to be Henderson's position to fill. But his meltdown upon joining Nottingham Forest on-loan effectively ended the 25 year-old's United career. Henderson's comments about his treatment being "criminal" was portrayed as just another swipe at United's much-maligned management team. But it was far more than that. It was an attack on his senior teammate. A senior teammate who finished last season as the club's Player of the Year - the fourth time in his career. And beyond De Gea, it was also an attack on sporting merit. On fighting for your place. De Gea saw Henderson's challenge and rose to it last season, proving in the process the managers who selected him correct.

And that's the dilemma which will soon face Costa. At €60m, at today's level, United won't blink in triggering his clause. But it'll only be done on his say-so. With the momentum gained at Porto. With the accolades now falling his way. Diogo Costa has much to think about.