Chelsea winger Christian Pulisic has been ruled out for six weeks due to a hamstring injury. The American winger could miss the start of the 2021-21 English Premier League season.
Pulisic suffered the injury during the 1-2 loss to Arsenal in the FA Cup final last Saturday.
"It's going to be touch and go for the start of the season. Six weeks probably gets into the start of the season, but we have to treat the injury right," Chelsea manager Frank Lampard was quoted as saying by the club's official website on Friday.
"In the big scheme of things, when Christian reflects on his first season, he should be very happy with his improvement levels. He's had the most goals and assists in his career, and that's in his first season in the Premier League.
"We'll get him fit and get him ready. If he misses the first one or two games, we'll have a firing Christian and hopefully as hungry as he looked after restart," he added.
Chelsea will take on Bayern Munich in the Champions League round of 16 second-leg meeting on Saturday night.
Asked if he really believed his team could turn around a 3-0 deficit from the first leg, Lampard said: "I believe we can, otherwise I shouldn't be here. We have to believe, more importantly the players have to believe as they take on this game.
"It's a huge task, no doubt. It's going to be extremely tough, but games have turned to big degrees, some famous games, great games, so we have to believe we have the opportunity to do something special.
"We have to go into the game with that thought, give everything to the game, play with confidence, and that's what I expect to see from the players. Not an attitude of this being a difficult match in a negative sense, it has to be a positive sense," he added.