Source: QO on Facebook
Immortals have not made any official comment about the roster change. Their latest official update regarding the Dota 2 team was earlier this month when the squad announced that they were adding Arif 'MSS' Anwar and parting ways with Sang-Don 'FoREv' Lee.
New year, new addition to Immortals Dota 2 roster. Please join us in welcoming @MSSDota to #IMTDOTA!Additionally, Immortals and @ForevDoto have mutually decided to part ways. We wish Forev the best. pic.twitter.com/kM2UUrJppc— Immortals (@Immortals) January 5, 2018
QO's decision comes within the drop period of the current roster lock, but unfortunately he's already registered with the team, having done so alongside his teammates on Jan 10. According to the rules, "once a player has accepted an invite, they're locked to that team's roster for the duration of the registration period." MSS has not registered to the team yet since only previously registered players may accept an invite during this first phase.
Source: Valve's roster registration site
Immortals are not completely without Qualifying Points this season. They've earned 90 so far thanks to a 3rd/4th finish at the PGL Open: Bucharest early in the season. That puts them third in terms of NA teams and tied for 15th/16th overall with Team Kinguin*.
Photo source: StarLadder