Midfielder Kyle Beckerman had been suspended for the game against Kansas City -- a punishment which Real Salt Lake was unsuccessful in overturning through appeal.
And Petke, who was ejected in the 72nd minute of the 1-1 draw, turned up at his postgame news conference with photographs of incidents he felt the league's disciplinary committee had gotten wrong.
Petke, after venting his frustration, said he expected to be punished. And MLS followed in kind on Friday afternoon, with Petke taking to Twitter to respond in pointed fashion.
He wrote: "I'll disclose my fine I believe in transparency and ACCOUNTABILITY. Accountability both from myself as well as all other party's. $3000"
In addition to Petke's sanction, the league fined two more coaches --Columbus Crew SC's Gregg Berhalter andNew York Red Bulls boss Jesse Marsch -- for their criticisms of referees.
The league also announced it has extendedFC Dallas midfielder Carlos Gruezo's one-match suspension for violent conduct to two games after review.
The Ecuador international was given a red card in the 58th minute of Dallas' match with the Vancouver Whitecaps when he wrestled midfielderYordy Reyna to the ground.
He was suspended for the match with the Philadelphia Union on Aug. 5, and now much sit out Dallas' Aug. 12 game against the Colorado Rapids as well.
Finally, MLS fined Chicago Fire forward Michael De Leeuw an undisclosed amount for being guilty of simulation/embellishment in his side's 4-1 victory over New England on Aug. 5.
WATCH: Mike Petke's epic post-match tirade
Real Salt Lake coach Mike Petke unleashed on referees in his press conference following their 1-1 draw against Sporting KC.
Philadelphia 3-1 FC Dallas: Sapong on fire
The Philadelphia Union thoroughly dominated FC Dallas at home, with CJ Sapong nabbing a brace, and VAR rearing its head.