New Borussia Dortmund coach Peter Bosz has injuries worries to contend with as the Black and Yellows' pre-season gets underway. For a number of players, it's their only chance to impress the new boss.Borussia Dortmund are back in pre-season training but a number of key players are unavailable to new coach Peter Bosz as he prepares for his first term in charge. The club confirmed on Monday that Portuguese international Raphael Guerreiro will be out for three to four months following an operation on a fractured ankle sustained at the Confederations Cup in Russia this summer. Initial scans in Portugal had originally diagnosed bruising but the 23-year-old will now be out until October or November. "We were surprised that our scans revealed a completely different picture than those in Portugal," said sporting director Michael Zorc. "[Guerreiro] will be a huge loss." Consequently, full-back Felix Passlack is likely to remain in Dortmund as his replacement, putting an end to interest from Hertha Berlin and VfB Stuttgart. Reus and Weigl also out Joining Guerreiro in the Dortmund treatment room are Julian Weigl, 21, who is still recovering from a broken ankle suffered away at Augsburg in May, and the perennially unlucky Marco Reus. After missing the bulk of last season with a pelvic problem followed by yet another muscle tear, Reus was sensational when he returned in April, scoring vital goals during a key stage of the season. But his injury woes continued when he ruptured his cruciate ligament in his right knee in the German Cup final and the 28-year-old again looks set to be out until the new year. It isn't all doom and gloom on the Dortmund injury front; Mario Götze is back in training after treatment for a metabolic disorder kept him out for much of last season. Battle for places Despite injury absentees, Bosz has inherited a 33-man squad which he considers to be too big – even with the Black and Yellows expected to compete on three fronts again this season. Crowd-favorite Neven Subotic is one of a number of players who will be looking to impress the new coach in pre-season. The 28-year-old spent the second half of last season on loan at Cologne and the arrival of Ömer Toprak in a 12 million euro transfer from Bayer Leverkusen means competition in centre of Dortmund's defense is tough. The futures of Sebastian Rode and Emre Mor are also certain. Mor has impressed with his tricky dribbling on occasion since joining Dortmund last summer but was too inconsistent to merit a regular place in former coach Thomas Tuchel's plans. Rode missed 24 games through injury last season and is likely to receive even fewer opportunities in midfield following the arrival of Mahmoud Dahoud from Borussia Mönchengladbach. Loan spell for Burnic In transfer news, highly-rated youngster Dzenis Burnic has been sent out on a year-long loan to newly-promoted VfB Stuttgart. The 19-year-old made his Bundesliga debut against Darmstadt last season and also featured briefly against Sporting Lisbon in the Champions League, but will hope to benefit from more playing time in Swabia, where he will rejoin his former Dortmund youth team coach Hannes Wolf. Borussia Dortmund's first pre-season friendly is against fourth-division Rot-Weiss Essen on Tuesday evening, before the team head off on their Asia tour from 13-19 July. They face Bayern Munich in the Super Cup on August 5.
