The Blues can seal their qualification to the knockout stage if the west London side beat Roberto Di Matteo’s men in Gelsenkirchen on Tuesday night.
Jose Mourinho’s Chelsea side, who are six points clear at the top of the Premier League table, lead Group G after two wins and two draws in four games.
And Belgium international Courtois is ready for the crunch European clash as he looks to reach back-to-back Champions League finals.
Courtois wrote on Instagram: “Training from today! Ready for tomorrow! C’mon Chelsea! #cfc”
Chelsea drew 1-1 with Schalke at Stamford Bridge earlier this season after Klaas-Jan Huntelaar cancelled out Cesc Fabregas’s opener.
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