We have introduced a decay mechanic to each player's Matchmaking Rating to adjust for inactivity. For example, if a higher-skilled A+ player takes a significant break from the game then we want to adjust so that when they come back they are not immediately playing at a level where they may not belong.
If a player is long-term inactive, at maximum they will derank to one rank below their starting position. For example, a Rank A+ player will go to the bottom MMR of Rank A. Meanwhile, a Rank B- player will go to the bottom of rank C+.
The decay-percentage is applied to the difference between your current MMR and the lowest possible MMR you can decay to and is then subtracted from your current MMR.
|Time Inactive||Penalty (of difference between ranks)|
|7 days||-2.5% of their potential max decay|
|14 days||-7.5% of their potential max decay|
|21 days||-15% of their potential max decay|
|28 days||-25% of their potential max decay|
|35 days||-50% of their potential max decay|
A player is in Rank X with 1000 MMR, and the rank below (ie, X-1) is between MMR 900-999 then the maximum potential MMR-decay for that player is 1000-900=100:
After 7 days the player has decayed -2.5%: 2.5 MMR lost (their MMR is 998.5 total)
After 14 days the player has decayed -7.5%: 7.5 MMR lost (10 total lost, their MMR is 990)
After 21 days the player has decayed -15%: 15 MMR lost (25 total lost, their MMR is 975)
After 28 days the player has decayed -25%: 25 MMR lost (50 total lost, their MMR is 950)
After 35 days the player has decayed -50%: 50 MMR lost (100 total lost, their MMR is 900)
The player is now at the bottom of Rank (X-1) and won't decay further unless they play again and become inactive once again.