London - Frank Lampard has accused Ross Barkley of showing a lack of professionalism after the Chelsea midfielder was pictured shirtless in a nightclub during the international break.
Barkley has been left out of Chelsea's squad for Wednesday's crucial Champions League Group H clash at Valencia as he continues his return from an ankle injury.
But, in his latest off-field incident, the 25-year-old was seen partying topless in Dubai recently, raising more questions about Barkley's judgement just weeks after he was involved in a dispute with a taxi driver after spilling chips in the vehicle during a night out in Liverpool.
Lampard backed Barkley publicly on that occasion, but this time there was a sterner tone to his response when asked about the former Everton star.
"There are two separate issues. One is the headlines this week. Ross knows how I felt about the first headline. I backed him then and I still back him now," Lampard said.
"But he showed a moment of a lack of professionalism as far as I'm concerned.
"It's something he now needs to show all his reactions on the pitch."
Although Lampard spoke out in support of Barkley following the taxi row, he still dropped Barkley for the following Champions League trip to Lille.
That was an early sign that Lampard is willing to be tough on his players. The recent revelation that he has ordered big fines for turning up late for training, among other offences, gave further credence to the belief that the Blues boss isn't to be trifled with.
Lampard remains adamant he isn't a hard disciplinarian.
"It's not something that I want to be a pure dictator because I understand that all my players are humans and have lives," he said.
"I don't police every moment of their lives. So I don't think it's a terrible thing that he's done."
"Ross has had an injury and he's still kind of carrying the injury, feeling a bit of pain when shooting, so he just has to work his way back in, in terms of the fitness, and train well.
"I certainly don't hold anything against my players. I like Ross, he's certainly one of my players."
The Barkley incident has overshadowed the build-up to an important European night for Chelsea, who are second in Group H, level on points with leaders Ajax and third placed Valencia.
A loss at the Mestalla Stadium would be a blow to Chelsea's hopes of reaching the last 16 and they will be without England winger Callum Hudson-Odoi, who suffered a minor hamstring injury on international duty.
Hudson-Odoi could be fit to face West Ham on Saturday, while Marcos Alonso was also absent from the squad that travelled to Spain.