The argument was sparked after Tolisso scored a goal against the team both Lewandowski and Hummels were playing for.

Passions are high even in training sessions for most top-caliber teams, but things nearly got out of hand today at Bayern Munich's camp.

Mats Hummels and Robert Lewandowski yelled at each other during today's training, according to Bild. The center back and the striker were playing for the same team in a practice game, and things got out of hand when Hummels lost the ball and Lewandowski chose not to carry on playing, deciding to tie his boots instead.

Hummels didn't hold back and criticized Lewandowski, who also had a thing or two to say about his team-mate. Here's Bild's recollection of the incident.

Hummels (H): Are you serious? You're seriously tying your shoes? Holy s**t. Shut up"

Lewandowski (L): "But you just lost the ball"

H: "Yes, it's my mistake, but you have an attitude problem"

L: "Mats, you constantly lose balls. Just focus and stop talking"

H: "Oh, get lost"

Despite the efforts of some of their team-mates to ease the tension, neither Lewandowski nor Hummels apologized for the incident. Bild claims both players kept their distance and didnt' try to make ammends.

Lewandowski's future has been under scrutiny recently, as reports claim that he will leave Bayern Munich to join Real Madrid this summer, and this alleged bust-up doesn't help to calm the rumor mill.