Pulisic, who joined in a £58 million deal from Borussia Dortmund in the summer, has started three of Chelsea’s six games in the Premier League this season while he was left on the bench for his side’s first Champions League group game against Valencia earlier this month.
According to Lampard, Christian Pulisic must impress in training to get a starting position.
The United States international was handed a start earlier this week as Chelsea hammered Grimsby Town 7-1 in the Carabao Cup on Wednesday evening.
And now Pulisic will be looking to retain his place in the side as Chelsea host Brighton at Stamford Bridge on Saturday.
‘I’ve got four wingers to choose from, now they are all fit,’ said Lampard.
‘Christian, I think we all forget, has just turned 21, because of the price tag, because he came through at a very young age.
‘It’s very normal to expect there to be an adaptation period and that’s what he’s in.
‘He’s showed some really good moments in pre-season, some good moments at the start of the season.
‘But what he has to do, as all the players not just the wingers, is reach levels in training daily when there’s competition in the squad that make you sit up and go, ‘here’s my team selection and that’s actually affected it by seeing good stuff.