"Ten minutes before the end of the game, the referee insulted Vero Salatic by saying he was an arsehole," refereeing director Carlo Bertolini told the federation's website.
The referee was upset after a shot by Grasshoppers captain Salatic hit him in the back during the match against FC Thun and the player joked that he should have got out of the way, Bertolini said.
"(Erlachner) immediately realised that he made a mistake and deeply regretted his action. Therefore, he apologised immediately after the match to the parties involved," he added.
"Such an incident should not happen to a referee, of course. We require all sides to display fair play, and the referee has to lead by example.
"Until now, Erlachner has displayed exemplary behaviour and has only been noticed by people thanks to his good performances. It's unfortunate that this one-off slip-up has happened."
Grasshoppers, second in the Swiss Super League, lost Saturday's home match 2-0 but fortune smiled on them on Sunday as leaders Basel were beaten 3-0 by strugglers Lucerne, their first home league defeat of the season.
Daniel Gygax and Xavier Hochstrasser gave the visitors a 2-0 halftime lead and Jerome Thiesson capitalised on a defensive blunder to add the third midway through the second half.
Europa League semi-finalists Basel, chasing their fourth successive league title, stayed three points clear of Grasshoppers at the top with seven games to go.
- Sports & Recreation
- Carlo Bertolini