Arsenal boss Mikel Arteta admits he is concerned about star striker Viktor Gyokeres after the Swede picked up a muscular injury during the win at Burnley on Saturday. The Gunners return to action this week in the Champions League when they travel to Slavia Prague, but they will face this test without their talisman up front after he missed training on Monday.Gyokeres has settled straight in at his new club, bagging six goals in 14 appearances across all competitions this season. Although he is yet to score against a top-half club in the Premier League, Arsenal fans have been impressed with their new striker's work on and off the ball as he continues to adapt to life back in England. But despite becoming a mainstay in the starting XI, the former Sporting man is expected to miss some time after being taken off at half-time during the 2-0 win at Turf Moor. That will include the latest instalment of Champions League action, as Arsenal look to maintain their perfect record in the competition in Prague.Speaking in his press conference ahead of the trip to the Czech Republic, head coach Arteta admitted he is worried about the extent of the 27-year-old's injury. He said: "I am concerned because he hasn't had many muscular issues, and he had to leave the pitch as he was feeling something. That is a concern for a player who is very explosive."The Gunners now find themselves in a familiar situation. With no Gyokeres, there is no recognised striker available for the club, with both Gabriel Jesus and Kai Havertz missing as well. The injury comes at an unfortunate time for Arteta, as his side look to maintain their six-point lead at the top of the Premier League table. As mentioned by the Spaniard, Gyokeres has never struggled with injuries in his career. The ex-Brighton and Coventry man has missed just five games for club and country in his career, but a muscle issue for a player who relies on being explosive with his movements is not a good sign. Rivals Tottenham had a similar problem with centre-back Micky van de Ven last season. The Dutchman - known for his pace and running power - tore his hamstring, the worst possible injury for a player of his type. Arteta will be hoping that the extent of Gyokeres' injury is far less serious. On top of Gyokeres, Havertz and Jesus, Arsenal are missing several other key players. Midfielder Martin Zubimendi also reported muscle discomfort during the Burnley match and was substituted late on for Christian Norgaard after receiving treatment. Although the Spaniard is suspended for the trip to Prague after collecting three yellow cards in the competition, he did take part in Monday’s training session, which serves as a positive sign ahead of the Gunners' Premier League meeting with Sunderland this weekend.Noni Madueke, who arrived from Chelsea in a £50 million deal during the summer, has been out since September with a knee injury picked up during a 1-1 draw against Manchester City. The winger avoided surgery and is reportedly pushing for a return to boost his chances of representing England during the upcoming international break.Club captain Martin Odegaard has endured a difficult season with recurring shoulder issues and a recent knee injury sustained in last month’s 2-0 win over West Ham. He has not featured since that match, though Arteta is optimistic that Odegaard, along with Havertz and Madueke, could be fit for the upcoming north London derby.If that was not enough damage to the Arsenal squad, Gabriel Martinelli has also missed the past two games after suffering a thigh strain late in the win against Crystal Palace in October. It means the London club must dig deep as we barrel towards the break, and hope that they can regain their core ahead of a crucial winter period as they push for the title.Every game will feel like a final for Arsenal this season, as they chase down elusive silverware under Arteta. They remain firm favourites to win the Premier League, and amongst the top dogs in the Champions League as well. But they have been here before, and it only takes one or two slip-ups for the title to slip from a team's grasp; that is a potential banana skin when they visit Sunderland on Saturday.