The striker was honest in his evaluation that his team are struggling after the stalemate on Saturday saw them fail to win in the league for a fourth consecutive time
The Gelsenkirchen side's winless league run stretched to four games as a late Julian Draxler strike cancelled out Igor de Camargo's opener for die Fohlen, leaving Schalke a full 13 points behind runaway leaders Bayern Munich.
The Netherlands international admitted that whilst he had not heard the booing emanating from the stands, he accepts that the Schalke faithful are not happy.
"I have not heard the whistles. But it is clear that people are not satisfied with how we've played," the 29-year-old was quoted as saying by Bild.
"When I'm on the pitch, it does not faze me. But clearly, we are not playing well."
Coach Huub Stevens was a little less forgiving towards the home support, instead praising his side for keeping the morale high.
"Compliments to the team for the morale. No compliment to a small portion of our fans. We wanted for [goalkeeper] Timo [Hildebrand] to have more peace in the stadium," the 59-year-old said.
"But unfortunately we did not succeed. It has not annoyed me much in the last few years, but today it did."
Schalke sit fourth in the Bundesliga, and travel to Montpellier in the Champions League on Tuesday evening.