Valve's quirky and popular 2007 title, Portal was rejected by Microsoft for Xbox Live.
Company marketing director Doug Lombardi beamed with enthusiasm about the possibility - "We'd love to do that. Right now it's something we'd love to do. I'd love to sell Portal on Xbox live" - but said size limitations and other factors drove Microsoft to reject it.
Nonetheless, he predicted the game will eventually show up on the service. "It always happens once it's been proven and I think it's been proven now on Steam, so I'm sure it'll migrate back to the consoles just like everything else does."
Portal was bundled as part of The Orange Box, which hit the 360, PS3 and PC last year, and netted the Game of the Year award at GDC in San Francisco.