Arsenal have a new injury problem before their Champions League game against Slavia Prague.

Their striker, Viktor Gyökeres, did not train on Monday after he was taken off early in the 2–0 win over Burnley.

The £55 million forward scored the first goal in that match but had to leave the pitch at half-time.

Coach Mikel Arteta said after the game that Gyökeres felt a “muscle niggle” and they didn’t want to take risks.

“That was one of his best games,” Arteta said. “He worked so hard and played very well. It’s just sad he felt something, so we had to remove him.”

Now, Arsenal’s attack looks thin because Martinelli, Havertz, and Gabriel Jesus are also injured.

Midfielder Mikel Merino, who came on for Gyökeres at Burnley, might play as a striker in Prague.

Young player Andre Harriman-Annous could also join the team for the big match.

To make things worse, goalkeeper Kepa Arrizabalaga also missed training for reasons not yet known.

Martin Zubimendi trained but can’t play in Prague because he’s suspended.

Arsenal have been in great form with nine straight wins, but this injury news could cause problems.

They also have important games coming up against Sunderland and Tottenham.

Gyökeres joined Arsenal from Sporting CP last summer and has scored six goals in 14 games so far.

The club’s doctors will check how serious his injury is before the game, but fans are worried he could miss more matches.