The European governing body said yesterday that Sergio Ramos and Xabi Alonso would both be investigated for possible "improper conduct" along with coach Jose Mourinho and team-mates Iker Casillas and Jerzy Dudek.
Ramos and Alonso were both dismissed by Scottish referee Craig Thomson late in Tuesday's 4-0 win away to Ajax Amsterdam after picking up second yellow cards for time-wasting.
The sendings-off mean they would serve automatic one-match suspensions in the final group game against Auxerre, which is a dead match for Real with the Spanish club already assured of first place in Group G and qualification for the last 16.
Both players had accumulated two yellow cards in the group stage before they were sent off and a further yellow card would have meant a one-match suspension during the knockout stage. Instead, they will start the knockout stage with a clean disciplinary slate, if their automatic suspensions are not increased by Uefa.
Spanish media reports said the players were acting on instructions from Mourinho. They said the message was passed by reserve goalkeeper Jerzy Dudek during a conversation with first choice keeper Casillas.
Spanish television has repeatedly replayed a moment during the match when the pair were seen talking with their hands over the mouths. Mourinho was also filmed with his hand over his mouth.
"There's no need to keep talking about this," Ramos told Real's website. "It's something which has been forgotten. It's time to turn over the page and think about the Clasico (Monday night's La Liga match against Barcelona). I don't fear any sanction because I don't believe that I've done anything illegal."
Mourinho could certainly have done without the distraction ahead of the Clasico, which sees both sides go into the match in terrific form. League leaders Madrid have won seven straight games and are coming off the 4-0 rout of Ajax, while Barcelona, one point adrift in La Liga, have won six straight matches including a record 8-0 thrashing of Almeria.
Real's Cristiano Ronaldo is the league's top-scorer with 14 goals - one better than counterpart Lionel Messi - and is certain Mourinho is just the man to stop a record four-game losing streak against their biggest rivals.
He said: "It's going to be an emotional meeting and we're in great form so I think we're gonna win. This Madrid is completely different to last season's and we haven't lost a single game in the league or the Champions League."