Manchester United bade farewell to Memphis Depay at the end of last week as the Dutch winger joined Lyon to resurrect his stalling career.
Just 18 months previously, Memphis had arrived from PSV Eindhoven with comparisons to a young Cristiano Ronaldo. He had been the Eredivisie top scorer and the youngster subsequently impressed with his confidence and charm when presented before the media for the first time as a United player. He later took the vacant number seven shirt in a bid to live up to his billing.
Memphis was largely poor at United, though. Flashes of brilliance against the likes of Club Brugge and FC Midtjylland aside, he struggled to make the kind of impact that he'd promised. The confidence that had been so visible promptly disappeared, and by the time he left for France he hadn't started a single Premier League game in 2016/17.
And yet, few fans were ready to fully write him off. He remains, even now, still only 22 years of age. It seems the club didn't want to cut ties too permanently either, because despite Lyon purchasing Memphis outright for around £16million, United made sure to insert a buy-back clause.
The clause will see Old Trafford chiefs maintain at least some control over the player's future, albeit without any hands-on input, while manager Jose Mourinho publicly expressed within hours of the Lyon sale that the door is wide open for Memphis to return to United..
It is a transfer tactic that is becoming increasingly common at the elite level, one that is replacing more traditional loans in certain circumstances, and is arguably significantly more beneficial to all parties as well.
Barcelona have been a major proponent of buy-back clauses in recent years. Rarely does a young player leave Camp Nou without some kind of first option that would allow the Catalans to bring them back at a pre-determined price should they begin to fulfil their potential.
Gerard Deulofeu joined Everton with a buy-back agreement in place, while Adama Traore's initial transfer away to Aston Villa was arranged similarly - Barça declined their option to re-sign the winger when he moved on to Middlesbrough. Alen Halilovic, Jonathan dos Santos and Andreu Fontas are among the others who were allowed to leave the club with buy-backs.
Seldom may they actually exercise them, but Barça did last summer when Denis Suarez made the return journey from Villarreal having initially been sold 12 months earlier. The midfielder has since become an important member of the first-team squad back at Camp Nou and has played 20 times in all competitions this season.
La Liga rivals Real Madrid activated a much more high profile buy-back clause last year when Alvaro Morata re-signed for the club after two seasons with Juventus. He was sold for €20m in 2014, established himself as one of the most promising young strikers in Europe, and returned to the Bernabeu in 2016 for the already agreed fee of €30million.
But more than just an insurance policy for clubs who may or may not be sure if they are quite ready to lose a player for good, there are obvious other benefits to buy-back clauses.
The life of a young player on loan can be uncertain at best and therefore a potential hindrance to overall development. An emerging talent may begin to thrive with greater first-team chances on loan, but it is so temporary that they will soon be back where they began within a few short months, struggling to then break into the team at their parent club and subsequently left to start from scratch with another loan somewhere else.
Countless young talents are lost this way, passed around from club to club, sometimes for years on end, without the opportunity to lay down off-field roots that could benefit them on the pitch. Chelsea's army of global loanees dotted at clubs around Europe is a prime example.
In a buy-back scenario, chances of game time for the youngsters have the potential to be better than as part of a normal loan as well, because a club has actually invested money and time into bringing them in, chasing them for a real purpose.
From a purely financial standpoint, clubs who insert buy-back clauses could actually profit out of them should they so wish. That was one of the scenarios that could have played out with Morata and Real Madrid, with rumours that Los Blancos would trigger their €30m option with the sole intention of selling him to any one of several interested clubs at twice the price.
For Manchester United and Memphis Depay, a permanent sale with a buy-back clause is the best scenario both parties could have wished for, while even Lyon have more control this way. The player has a fresh start somewhere new, and the club don't have to completely give up on a clearly talented individual that may still come good in time.
All in all, buy-back clauses are only going to become more and more common.