BT SPORT
Barkley, who had just six months remaining on his Everton contract, this week left his boyhood club for Premier League champions Chelsea in a £15m deal.
And while Lampard believes Chelsea have done great business, he told Barkley to prove to Antonio Conte that he can perform week in, week out.
The former Chelsea midfielder felt the 24-year-old was too inconsistent in terms of form during his time at Everton.
“It’s a no-brainier,” Lampard told BT Sport.
“I think £15m for someone of the ability of Ross Barkley it’s a great deal for Chelsea.
GETTY
How Ross Barkley could fit into Chelsea’s line-up
GETTY
“At Everton he was allowed to do it in fits and spurts, he won’t get away with that at Chelsea”
Frank Lampard
“We’ve talked about him for a while though and he hasn’t fulfilled his potential.
“But there are players in this market who are moving for £30m or £40m who are of a lesser ability.
“Now it’s up to Ross, though. At Everton he was allowed to do it in fits and spurts. Five games here and six games there.
“He won’t get away with that at Chelsea. He’s got to be disciplined, work hard and show he’s capable of adding things to his game.
“I think he can do it but it’s down to him now.”