The sanction sees the Fulham full-back become the first player to be suspended under a new pilot scheme by the Football Association, in which three former referees review footage of indiscretions not seen by match officials.
Riether's offence occurred in the closing stages of last weekend's encounter at Craven Cottage, but was missed by referee Lee Probert, triggering the need for an assessment by the new panel.
In a statement on Wednesday afternoon, the FA said: "Following an Independent Regulatory Commission hearing today, Fulham’s Sascha Riether has been suspended for three matches with immediate effect after he accepted an FA charge for violent conduct."
The German took to Twitter on Tuesday to apologise for the stamp.
"I want to say I am sorry to Adnan Januzai (sic)," he tweeted. "It was very unlike me and I can only say that frustration got the better of me.
"I also want to apologise to my teammates, fans and everyone at the Club, for the ban incurred following Saturday's match.
"I will accept the consequences of my actions, and hope to put it behind me when I return."
Riether is set to miss Premier League fixtures at Liverpool and West Ham, as well as a home clash with Swansea City.
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