Schalke striker Klaas-Jan Huntelaar is out for the next four weeks after tearing knee ligaments and misses Wednesday's UEFA Champions League play-off, first-leg tie at home to Greek side PAOK.
Huntelaar, capped 60 times by the Netherlands, is a key player for Schalke having scored 80 goals in 121 matches in all competitions. Schalke host PAOK at Gelsenkirchen's Veltins Arena for the first leg on Wednesday with the away leg to be concluded in Greece the following week.
The Dutch international, who scored twice in last Sunday's 3-3 draw at home to Hamburg, tore the medial ligaments in his right knee as Schalke were beaten 4-0 at Wolfsburg in the Bundesliga on Saturday. The club's medical staff expect the 30-year-old to miss at least the next four weeks.
Schalke can become the fourth Bundesliga club in the UEFA Champions League if they see off PAOK, who are coached by ex-Schalke boss Huub Stevens. Hungary striker Adam Szalai, who cost Schalke eight million euros from Mainz in the off season, is expected to take Huntelaar's place in the starting line-up.
Schalke coach Jens Keller called the players in for extra training on Sunday after the heavy defeat at Wolfsburg left them with just one point from the first two league games.