Pulisic will miss Chelsea's Champions League clash with Rennes at Stamford Bridge on Wednesday, but Blues boss Lampard expects him back in action without much delay.

"Christian had a scan yesterday that showed a very, very minor injury to his hamstring, very minor," said Lampard.

"So he's already back outside. He won't be fit for tomorrow, but we'll see after that.

"It is obviously a relief for the injury to be minor.

"He made the right decision in not attempting to play the game, because he could have made it worse.

"So it's clearly a relief that he will be back very soon, because he's an important player for us."

Pulisic tore a hamstring in Chelsea's 2-1 FA Cup final defeat to Arsenal in August, and has a history of muscle issues.

Lampard revealed Chelsea have been working hard to limit the pacy forward's issues ever since his arrival at Stamford Bridge, but conceded that speed-based stars can always fall victim to such injuries.

"With the actual muscle injuries, it's a hard one to call, it's forever going to be a challenge," said Lampard.

"Some players that play on the edge, have such speed and acceleration in their game, maybe they can be more susceptible.

"I don't think that's a one-fits-all answer, because it's different for everybody.

"From last season we were looking at ways of managing Christian and looking at ways of being proactive in not hopefully getting so many injuries, I know that's something he's experienced previously in his career at Dortmund as well.

"So we're all working in the same direction on that one, to try to get him to be as fit as regularly as possible, because we all know his talent."