Europe's top club coaches are split over the wisdom of using sin bins to punish footballers during matches, management legend Sir Alex Ferguson said on Thursday.
Ferguson said the issue was squarely in the spotlight at a closed-door meeting of 18 coaches, which he chaired at the Swiss base of European football's governing body Uefa.
"That was quite a long discussion, on the various aspects of a different nature: serious foul, simulation, disrespect to the referee," Ferguson told reporters.
"But we couldn't get to an agreement about it because it's such a controversial decision to change from what we know to a sin bin," said the former Manchester United coach, who retired in 2013 after 26 years in charge.
"I think that simulation by players has become a disease in the game. There's no question about that," he added.
Temporarily excluding an offending player from a match is a disciplinary tool in rugby union and league, or ice hockey.
Proponents say that what is good enough for those sports is also worth considering in the world of football.
Critics underline that football referees already have four degrees of sanctions for foul play – a free-kick, a penalty, a booking or a dismissal – and argue that a fifth option is pointless.
Ferguson noted that referees were also divided over the issue.
The two-day Uefa meeting, which is an annual event, drew names including Arsenal boss Arsene Wenger, Chelsea's Jose Mourinho, Real Madrid's Carlo Ancelotti, Luis Enrique of Barcelona and Bayern Munich coach Pep Guardiola.
"The area we spoke most about was tactical fouls, which prevent a player from progressing in the match, someone's on the halfway line and he pulls the jersey back, that was discussed," said Ferguson, adding that that was a clear yellow card offence.