Football's lawmakers have delayed plans to publish details of sin-bin trials at higher levels of football until next month, the PA news agency reports.
Trial protocols on sin-bins, plus other measures to combat poor player behaviour, were expected to be published on Friday, but it is understood they will now be the subject of further discussion at the International Football Association Board's annual general meeting at Loch Lomond on 2 March.
PA reports that the protocols will not therefore be published before then.
It is unclear precisely why the IFAB has chosen to delay the publication and which aspects of the protocols remain under discussion.
Sin-bins have been used in grassroots football successfully for a number of years, but the IFAB indicated at its annual business meeting in November a willingness to test them at higher levels.
It is understood that in these planned trials players would be shown blue cards for dissent and tactical fouls, such as Giorgio Chiellini's cynical tug on Bukayo Saka for Italy against England in the Euro 2020 final.
The introduction of a blue card, if it passed into the laws of the game, would mark the biggest single change in managing player discipline since red and yellow cards came into force at the 1970 World Cup.
It is understood the plan was not to test sin-bins in top-level competitions initially and stress test them in lower-level events. This is understood to be because of concerns about the impact on players coping with different rules being used in a domestic league and a continental competition for instance.
It is unclear precisely what level the IFAB had in mind for these trials, but certainly a higher level than the grassroots game.
The agenda for next month's AGM published earlier
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Giorgio Chiellini