Christian Pulisic's attempts to put his fitness issues behind him remain a "work in progress" according to Chelsea head coach Frank Lampard.

The USMNT international scored his first Premier League goal of the season in last Saturday's 3-1 win over Leeds, coming off the bench to make only his fifth appearance in the competition due to lingering hamstring problems.

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Pulisic sustained the original damage in August's FA Cup Final defeat to Arsenal and Lampard has previously suggested the 22-year-old could be put on a specifically tailored training programme in an effort to reduce a susceptibility to injury which was evident prior to his £58 million move from Borussia Dortmund last summer.

Chelsea travel to Everton on Sunday and ahead of that match, Lampard said Pulisic was not 100% fit but could still have risked him in Tuesday's Champions League draw with Krasnodar had the circumstances been different.

"Christian Pulisic had a tiny bit of awareness off the back of the Leeds game with one of his hamstrings but he was training normally so we should be as we were [with players available to play Everton]," Lampard said. "With Christian, it is a work in progress.

"I don't want to call this an injury that he had in midweek. If the game had been a different type of game, it may have been one where I would have felt I would have used him.

"We know his abilities, that's very clear. He showed them when he came on against Leeds last week. I just have to find the right way to get the best out of him regularly and consistently."

Chelsea will also be without Hakim Ziyech and Callum Hudson-Odoi due to hamstring injuries.