Arsenal boss Arsene Wenger reportedly admonished Jack Wilshere for smoking on holiday when the England international returned to pre-season training.
Wilshere was pictured with a cigarette at a pool party in Las Vegas earlier this summer, and upon his comeback to the Gunners' London Colney training complex, Wenger gave him a stern dressing down.
The Mirror reports that in a private meeting in Wenger's office, the French boss was critical of his player's behaviour and warned him that he risked failing to fulfill his potential.
Arsenal were beaten 1-0 by the New York Red Bulls on Saturday.