Gavin Verhey told the story of phasing and its return to modern Magic in today’s episode of Good Morning Magic.
Phasing debuted in Mirage back in 1996 and showed up in cards throughout the block, but due to its confusing nature and lackluster gameplay, the mechanic phased out for quite a while after the block. Phasing was hard to track, tough to understand, and made cards close to unplayable as paying mana for a creature to only be around every other turn wasn’t worth the mana or card.
In 2005, phasing made a slight return as it got put on some older cards like Oubliette via errata to cleanup some designs and text boxes.
But when Verhey was working on Commander 2017, he came up with a card that gave you protection from everything and exiled all your permanents until the the end step of the player to your right.
This card had some issues; the wording was cumbersome as it had to have the “player on your right” clause so that your creatures wouldn’t be summoning sick, and also the mass flicker was overpowered in conjunction with landfall and other enters-the-battlefield effects. But rules manager Eli Shiffrin suggested the card should just have phasing to clean it up. Suddenly, the first new black-bordered card with phasing in twenty years was made.
This led the design team to revisit phasing and realizing that while permanents with the ability were failures, the spells that made things phase out as a one-shot ability were solid designs. Having phasing work as a tool to help deal with creatures temporarily returned to Standard with Teferi, Master of Time in Core Set 2021. Players liked and played the card, giving the green light to bringing back phasing in other sets. Out of Time showed up in Modern Horizons 2 while Divine Smite, Guardian of the Faith, and Blink Dog appeared in Adventures in the Forgotten Realms.
Verhey wrapped the video up by saying you can expect to see more phasing cards coming down the line with white being the main color to utilize the ability.