Schalke kicked both Kevin-Prince and Germany winger Sidney Sam out of the squad, and suspended midfielder Marco Hoeger, 10 days ago following their shock 2-0 league defeat at Cologne.
The defeat threatened to jeopardise Schalke???s place in the top six of the Bundesliga after Die Knappen failed to qualify for next season Champions League for the first time since 2010/11.
Boateng, 28, remains under contract with Schalke, but is allowed to talk to other clubs to negotiate a transfer and has already been linked to former club AC Milan.
Schalke have told both Sam and Boateng – who enjoyed spells at Tottenham and Portsmouth in the Premier League – that they have no future with the club, a decision which has led Jerome to insist Kevin has been treated unfairly.
“They were clearly looking for a scapegoat,” he told German magazine Bild. “My brother hadn’t played for weeks in the starting side.
“Just because he started one game in the team, which has been playing without success for weeks, he is supposed to have suddenly pulled the whole team down?
“He doesn’t have an explanation for the sudden turn of events, he is naturally very disappointed with those responsible at Schalke, which I can completely understand.
“Why wasn’t the whole team criticised for the defeat? Instead, they threw two players out, one of whom also spent five weeks on the bench with Kevin, and had still done all they could.”
The German professional footballers’ union, the VDV, has urged Sam and Kevin-Prince to take legal action against Schalke, who will pay their contracts until they expire in 2018 and 2016 respectively unless they are sold.