In an unusual move, Wizards of the Coast has instituted an "emergency card ban," removing the Felidar Guardian card from Standard play, effective immediately. The ban is an addendum to the gamemaker's most recent list of banned and restricted cards which was released earlier this week.

According to WotC's official statement (reprinted in full, below), the card has been removed from play due to the "Copy Cat combo," a move which saw the card used in combination with the Saheeli Rai card. When played together, the player could amass a virtual army of cats, overpowering opponents through sheer numbers. While the banning itself is not an unpopular move -- many players have long felt the card should be removed from Standard play -- WotC has been criticized for its timing of the ban.

WotC estimates that the rule will affect approximately 40% of the decks used in official tournaments.

Felidar Guardian is being banned effective Friday, April 28.

Why are we making this call now and why didn't we make it in our regular B&R announcement on Monday? The answer is data. We knew going into Monday that the Saheeli-Felidar combo was a significant issue for Standard and were watching it closely. Our rationale for waiting was to make sure we only needed to take one and only one action to correct the Standard environment. Our plan was to monitor early play behavior and pro competition and make a call following Pro Tour Amonkhet.

Since the initial announcement, for the first time ever, we pre-released a new card set on Magic Online before the formal release date. This happened on Monday. What we expected to take a few weeks to understand has ended up taking two days to form a clear picture of a metagame unbalanced by the Copy Cat combo, as even its natural predator, Mardu Vehicles, fell behind. Couple this with consensus among a wide sampling of pros and feedback (and pizza) from our community and we decided to take action.

Saheeli-Felidar's win-loss ratio and metagame share has actually increased since the release of Amonkhet. In Magic Online Standard Leagues since Monday, Saheeli combo has made up approximately 40% of 5-0 and 4-1 decklists—up from prior to Amonkhet's release. While we never take decisions like this lightly and recognize this is a change from the norm, when a plurality of the data points in a clear direction, we will take action.

We also understand we shouldn't let combos like Saheeli-Felidar get out the door in the first place. For that we take ownership and are making changes to try to prevent this from happening again. But our highest priority is keeping Magic fun and enjoyable for our players. We believe this banning coupled with a number of internal testing process improvements will be significant steps toward making Standard the fun, dynamic format we all want it to be in perpetuity.

Via Kotaku