Chelsea’s pre-season standoff with Borussia Dortmund, which ended in a draw, brought with it an unfortunate setback as Christopher Nkunku went down with an injury.

Chelsea’s recent acquisition needed a substitution after just 22 minutes in Chicago. The Blues, under Mauricio Pochettino, got off to another strong start thanks in large part to the Frenchman’s strong early connections with Nicolas Jackson.

Nkunku, though, was unable to shake off an early tackle and limped off the field in the 22nd minute. Both sides had trouble making a convincing final third push on the terrible field at Soccer Field in Chicago.

Christopher Nkunku goes off early with injury

Dortmund took a late lead thanks to a goal from Marius Wolf. However, a late header from youngster Mason Burstow, though, kept Pochettino undefeated in his first pre-season with the Stamford Bridge outfit.

The playing surface at Soldier Field was uneven from the get-go due to recent musical performances by Ed Sheeran, Beyonce, and Taylor Swift. Twenty minutes into the game, though, he went down clutching his knee after getting his leg trapped in the ground while wrestling Mats Hummels for possession.

Mauricio Pochettino provides update on striker

Again starting on the left against Dortmund, Nkunku has been one of the most exciting players in pre-season and has scored three goals. Now Chelsea‘s medical team will need to check up on the 25-year-old further.

Some knee pain bothered the former Leipzig striker knee pain, according to Pochettino in his postgame press conference.

“The doctors are checking him and I hope it is not a big issue. He fell in the action which was maybe a penalty and he feels something in his knee but we hope it is nothing big. We hope he can be back quickly with the team. We need a few days to assess him.”

Pochettino did not blame the field in particular. He did say the conditions did not provide the best chances for safety. Traditionally, the ground at Soldier Field is for NFL games.

“We took some risks because the pitch is not perfect because the facilities are used for a different sport. We won’t blame the pitch for the injury though. For me, it was bad luck.”