Coke has only just joined Schalke, but injured his cruciate knee ligament in his first match.
New Schalke signing Coke has suffered a cruciate knee ligament injury on his debut for the club, and is facing a potentially lengthy spell on the sidelines.
The Bundesliga club sealed the 29-year-old's signing from Sevilla last Sunday, but received a massive blow in the defender's first match.
Coke played in the first half of Schalke's 2-1 friendly victory over Bologna in Austria on Thursday, but picked up the injury from what the club described as a "heavy challenge" and is now set for a long-term absence.