Did Schalke sack Gross because he did not know players names?

It is not been an easy season for Schalke 04. The German side, bottom of the Bundesliga table, have just nine points from 23 games and just one win.
Changing coaches has done little to help. Four of them have been dismissed. David Wagner, Manuel Baum and Huub Stevens were the first three, but Gross' dismissal is much more interesting.
Schalke sacked him after losing 5-1 to Stuttgart. According to the club, this result and the 0-4 loss to Dortmund in the derby were the reasons for his dismissal. Another reason has been mentioned though.
'Sport' reports that key players like Huntelaar, Mustafi and Kolasinac reportedly complained that Gross was not calling them by their names. The now ex-coach kept on mixing them up and that was something which irritated the squad.
As well as the coach, the club sacked the sporting director Jochen Schneider, the delegate Sascha Riether and fitness trainer Werner Leuthard.