The lineup of games coming to Xbox One in fall 2015 is so deep that Microsoft may need to shift some titles to 2016 so the games that are released during next year's holiday season have a chance to breathe. That's according to Head of Xbox, Phil Spencer, who spoke about the congested release slate recently.

"Looking at production schedules and how things are lining up, next fall is just crazy," Spencer said during the latest Major Nelson Radio podcast (via VideoGamer).

"I mean, this fall from a first-party/third-party standpoint is great. Next fall, I don't... Honestly it's not hype at all, I honestly don't know that we can actually ship all the stuff that thinks it's trying to ship next fall," he added. "It just might be too crowded and we might purposely try to move some things out to spread it. You have to [give them some breathing room], you have to do that."

"Honestly it's not hype at all, I honestly don't know that we can actually ship all the stuff that thinks it's trying to ship next fall" -- Phil Spencer

Microsoft has not revealed its official holiday 2015 release slate for Xbox One just yet, but we already know some of the game that are scheduled to be released then. Two first-party Xbox One games confirmed for holiday 2015 include Halo 5: Guardians and Rise of the Tomb Raider. Quantum Break is also scheduled for 2015, while Scalebound does not yet have a release date.

The company is also working on a new Gears of War game for Xbox One, as well as Fable Legends for sometime in 2015. Meanwhile, Spencer will see a pitch for the next game from Rare Ltd. this month. On top of those games, Spencer teased previously that Microsoft is working on a new IP that will "push the boundaries."

Also during the podcast, Spencer said games can thrive in release windows other than holiday. February/March and May can be successful months, he said, citing examples such as Red Dead Redemption (May 2010) and various God of War games.

"It's nice as an industry that we don't all have to get on top of each [other], just clobber ourselves and compete against one other, because there are enough hours in the year for a gamer to go play great games, but people want to play the things that are current," Spencer said.

"And I think as publishers and first-parties have success at multiple points of the year it's just a good thing for us," he added. "Because having three/four great games ship all in the same week at the end of October, while maybe on some forecast somewhere it feels like that's the right thing to do, just as an industry I think it's much more healthy if we have more beats throughout the year where people can ship great games."