Sir Alex Ferguson has thrown his weight behind calls for plans to introduce sin-bins in football in an interview with the Big Issue.
There is increasing debate over whether the sport should bring in the ruling, which has proved a success in rugby and ice hockey and sees players punished by being sent off for a short period of time.
UEFA president Michel Platini had previously hoped to introduce a white card to punish protests to the referee, although FIFA president Sepp Blatter rejected that proposal. Platini had wanted a card that would land a player with a 10-minute temporary sending-off if they were overly aggressive in their protests.
Former Manchester United manager Ferguson, currently a member of a UEFA technical study group, revealed that it is considering the idea of introducing sin-bins as well as increasing the number of substitutes to 11 in European finals.
"I chair a forum of elite coaches that meet every year and I'm a member of the technical study group of the Champions League and the European Championship," Ferguson said in an interview in this week's edition of the Big Issue, out on Monday.
It's Fergie time! pic.twitter.com/3U2n5r1s6J
- The Big Issue (@BigIssue) November 17, 2014
"So I'm still involved in football at the highest level. Right now, we're looking at the possibility of introducing sin-bins like they have in rugby -- a 10-minute suspension during the match. But we want to be careful that somehow it isn't exploited if it's introduced.
"We're also looking at allowing 11 substitutes on the bench for big finals in Europe. That way you can recognise the contribution the squad's made and allow a wider range of substitutions."
UEFA has already ruled that, from this season, yellow cards will be wiped out after the quarterfinal stage of the Champions League and Europa League to make sure players do not miss the final through suspension - a move Ferguson approves of.
"We lost Darren Fletcher from the 2009 Champions League final against Barcelona and also missed [Roy] Keane and [Paul] Scholes for picking up cards in the 1999 Champions League final against Bayern Munich," he said. "Now, they'd all played in all the previous rounds, so it wasn't fair that they missed out."