Leon Goretzka's camp are reportedly 'irritated' with Bayern Munich amid links of a transfer to Manchester United.
The 26-year-old is a key player for the German giants, who picked up their ninth successive Bundesliga title in May.
In spite of his pivotal role in Bavaria, negotiations over a new contract have been described as 'slow' by Sport Bild and the Red Devils have reportedly table an offer for the central midfielder.
With Paul Pogba set to depart for Paris-Saint Germain this summer, Ole Gunnar Solskjaer is on the lookout for a replacement and the Bayern powerhouse is said to be high on his wishlist.
Goretzka's contract also expires next summer and his former agent, Jorg Neubauer, recently retired.
That left Neubauer's wife in charge, assisted by Thomas Kroth, a highly-rated Bundesliga agent.
Reports in Germany claim United have offered the powerhouse a reported £200k-a-week deal when he becomes a free agent.
After signing for free from Schalke in 2018, Goretzka has clocked up 112 appearances for Bayern, scoring 25 goals and laying on 27 assists.
He scored one goal in his three outings at Euro 2020, scoring a late equaliser to send Germany through to the round-of-16, only to be beaten by England at Wembley.
Incoming Bayern boss Julain Nagelsmann is a big fan of Goretzka, recently telling Sport Bild : "Leon is one of the best box-to-box players in Europe.
The ex-RB Leipzig manager added: "He has incredible goal threat and knows when to bomb forward."
Although United are said to be in pole position, Real Madrid and Barcelona are also labelled as interest, although both Spanish clubs are currently strapped for cash and would also likely have to wait until 2022.
Bundesliga commentator Ian Darke recently singled out two reasons why the Bundesliga star would improve Solskjaer's side.
Speaking to ESPN FC, Darke said: "There's talk they may try to get Leon Goretzka, which seems a bit of a flyer but I've heard that mentioned, from Bayern Munich, because I think his contract is moving towards its end.
"He may give them a little bit more drive and dynamism through the middle and maybe a few more goals as well.
He added: "It's not my decision but you can see it might make sense."
With a similar skill set to Pogba, Goretzka's eight goals in 10 fewer games than the Frenchman last season is certainly encouraging for Red Devils supporters.
Following the £73million arrival of Borussia Dortmund winger Jadon Sancho, Solskjaer signed a new contract at Old Trafford on Saturday.
The Norweigan told the club's website : "I can’t say we’re delighted with what’s happened so far because we haven’t won anything, but still, like what I’ve just said, the progress is there and I feel the squad is in a much better place and I think we’re gradually getting there by just what we’re doing every single day.
"We haven’t got a trophy to show for it, but I think we feel stronger and ready for the next challenge."