343 Industries hasn't ruled out the possibility of bringing Halo Reach and Halo 3: ODST to Xbox One in the future, telling VideoGamer.com that so many people "have asked about it that we are thinking about it".
"With Halo 5 coming out we really wanted to focus on those Master Chief-centric games," executive producer Dan Ayoub explained, discussing the reasons why the two games had been left out of Halo: The Master Chief Collection with us earlier this month.
"That was part of it. Quite honestly, the other part of it was just disc space. We're squeezing everything we can out of the available space for this thing.
"What I can tell you is probably the biggest question we get from people is, what about ODST and Reach. What I can say is it's certainly not in our development timeline or planning right now [but] we've heard that question so much that it has seeped into our collective subconscious. I think enough people have asked about it that we are thinking about it."
Halo: The Master Chief Collection contains four Halo games, including Halo: Combat Evolved Anniversary, Halo 3 and Halo 4, plus a Halo 2 remaster built specifically for Xbox One.
Look out for it exclusively on Xbox One from November 14.