SNK confirmed the bouncy fighter for The King of Fighters XIII on a splash page. Location tests at Hey begin today. SNK plans to release the Taito Type x2 arcade game in Japan this summer.
No news about North America or console versions at this time.
Update: Z_merquise points out Mai isn’t the only character from the girls team returning in The King of Fighters XIII. King and Yuri are in the game too. Thanks for pointing this out!