Alexis Sanchez in bust-up with Mason Greenwood?

Manchester United forward Alexis Sanchez has reportedly been involved in a training ground bust-up with club graduate Mason Greenwood.

Sanchez has just returned to training following a hamstring injury picked up on international duty and he is anticipated to return to first-team action by the end of the month.

As such, he has been increasing his fitness levels in training alongside his teammates but The Sun reports that the process has not gone smoothly as planned.

The former Arsenal man has suffered several minor injury setbacks since his move to Old Trafford and he is understood to have exchanged foul words with Greenwood in training following a strong challenge from the latter.

While Sanchez remains out of the first-team picture, Greenwood has been earning plenty of plaudits from the fans after an impressive pre-season campaign with United.

He was only afforded with a cameo role off the bench during the club's 4-0 win over Chelsea in the league opener, but stands the chance of receiving more gametime as the season progresses.