There has been a lot of talk about Robert Lewandowski's future at Bayern Munich in recent days.

The Polish striker has been a real goal machine since arriving in Bavaria from Borussia Dortmund back in 2014, a free transfer which is viewed by many football fans as one of the finest pieces of business ever.

However, the 29-year-old may opt for a new challenge come the summer, with Sky Germany suggesting that he has indeed rejected a new deal and opened talks with Real Madrid - a club he has been rigorously linked with throughout his career.

The Sun even reported that Premier League giants Chelsea and Manchester United were firmly in the race for the unsettled striker, so with all these rumours circling, you have to feel that there is some element of truth.

And, to add further fuel to the fire, it appears all is not well with Lewandowski amongst his teammates at Bayern.

On Tuesday, reports surfaced from German publication BILD stating that there had been a very heated exchange between the Polish hitman and defender Mats Hummels - the two also played together at Dortmund.

A transcript of what was said between the pair was also published and it certainly wasn't pretty.

LEWA & HUMMELS CLASH

The two were on the same side in a training match and when Corentin Tolisso scored a winning goal for the opposing side, Hummels said: "Are you serious? You're seriously tying your shoes? Holy shit. Shut up."

Lewa to Hummels: "You just lost the ball."

Hummels to Lewa: "That's a mistake. But with you, that's the attitude."

Lewa: "Mats you constantly lose the balls, just talk."

Hummels: "Oh, shut up! Get lost."

In the final runnings of the game, there was no contact or apology from either player and they also refused to shake hands after the final whistle.

And, to make matters worse, both continued to avoid each other on the training complex after.

Not the kind of nonsense Jupp Heynckes needs right now, with the German giants looking to finally win the one trophy that has eluded them in recent years; the Champions League.