Barkley has attracted negative headlines twice in recent months after he was reportedly involved in an incident with a taxi driver earlier this season.
The Blues midfielder has been suffering from an ankle injury over the last few weeks, and Lampard had some words of advice for the England midfielder this week.
Speaking at a news conference before Chelsea FC’s clash with Valencia in the Champions League, Lampard said on Tuesday: “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. But he showed a lack of professionalism as far as I’m concerned.
“It’s not something that I want to come down hard on, because I understand all my players are humans and have lives. I don’t police every moment of their lives. So I don’t think it’s a terrible thing that he’s done.
“But Ross has had an injury, he’s still kind of carrying an injury, so he just has to work his way back in and train well.
“I certainly don’t hold anything against my players. I like Ross and he needs now to show all his reactions on the pitch.”
The 25-year-old Barkley has made six Premier League appearances for Chelsea FC so far this season, starting five times in the top flight for Lampard’s men.
Chelsea FC will return to Premier League action on Saturday afternoon when they host West Ham United in the Premier League.
The Blues are aiming to get back to winning ways in the top flight after they were beaten 2-1 by Manchester City at The Etihad last weekend.
The west London side are currently in fourth place in the Premier League table as they chase Champions League qualification this season.
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