Manchester United's transfer policy under Erik ten Hag has revolved around known quantities.

Ten Hag has had less than three full transfer windows at Old Trafford but United have already spent more than £150m on players that their Dutch coach has managed in the past. The arrival of former Ajax goalkeeper Andre Onana is merely a continuation of the policy that brought Lisandro Martinez and Antony to the north of England.

If United are intent on sticking to the reunion strategy, they may be tempted to dip their toe into the free agent market. Here are some of the free transfers with an all-important link to Ten Hag that last season's League Cup winners could snag this summer.

Lucas Moura

"Football can be very beautiful," Ten Hag mused after steering Ajax to their first Champions League semi-final since the 1990s. "And it can be very cruel."

At half-time of the second leg, Ajax led Tottenham 3-0 on aggregate. Ten Hag warned his players about a possible comeback but could scarcely have predicted Lucas Moura's second-half hat-trick, sealed in the 96th minute, to send Spurs to the final in Madrid.

Four years on from that cruel evening, Moura has come to the end of his Tottenham contract, giving Ten Hag the chance to have the Brazilian on his side this time.

Sander van de Streek

Despite scoring on his league debut for FC Utrecht after Ten Hag signed him in the summer of 2017, Sander van de Streek enjoyed his best form for the club once his coach had been poached by Ajax mid-season.

Across the final 11 games of the 2017/18 campaign, Van de Streek rifled in seven goals (and created another three). The box-crashing midfielder saw out his deal at Utrecht this summer and could be given another chance to show Ten Hag his full value.

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Mark Diemers

Mark Diemers had been at FC Utrecht for four years but lasted just six months before Ten Hag deemed him surplus to requirements, sending the midfielder on a loan which turned into a free transfer to De Graafschap.

When Ten Hag was appointed Manchester United manager, Diemers praised the coach's "insanely good" tactical training sessions but warned: "I just didn't think he was very good at the time on a human level."

However, the pair have fired off sporadic text messages to each other in the intervening years and Diemers stressed: "He has undoubtedly grown at a human level." Perhaps one of the next digital exchanges between the pair will involve a contractual offer.

Dario Dumic

Ten Hag hailed Dario Dumic as a "real killer" when he signed the centre-back during his final summer as Utrecht manager in 2017. However, the then-25-year-old spent most of his six months under Ten Hag killing time on the substitutes bench.

Even after Ten Hag moved to Ajax, Dumic struggled for playing time under his successors at Marco van Basten's boyhood club.

After finishing bottom of the German second-tier with SV Sandhausen last season, a jump straight to Manchester United would represent a staggering career arch - especially for a 31-year-old. However, after spending time under Ten Hag's tutelage, Dumic's chances of a transfer to Old Trafford aren't entirely impossible.

Patrick Weihrauch

After steering Go Ahead Eagles to promotion during his first season of senior management, Ten Hag took the seemingly backwards step of coaching Bayern Munich's second team in the German fourth tier.

Ten Hag used the two years wisely, soaking in as many secrets as he could prise away from the first team coach Pep Guardiola. When Ten Hag wasn't gawking at the senior side's training sessions, he was overseeing a team that had Patrick Weihrauch at its epicentre.

While he made more than 100 appearances for Bayern II, Weihrauch never got a run out for the first team.

Now 29, Weihrauch has come to the end of his time with Dynamo Dresden in Germany's third division. A reunion with Weihrauch may even go beyond Ten Hag's iron-clad loyalty.

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This article was originally published on 90min as Five potential free transfer targets for Manchester United with links to Erik ten Hag.