Players have to have appeared in a match within the qualifying period to appear in the lists (normally 12-15 months for Tests, 9 -12 months for T20s and ODIs). For example, Parthiv Patel lost his place in the Indian Test side in 2008 and disappeared from the lists in 2009. But he retained a rating which slowly diminished as he missed matches. He was then picked again 2016 and returned to the rankings. If a player confirms his retirement he is also removed from the list. So, for example, MS Dhoni retired from Tests in 2014 and was removed from the Test rankings - but he remained in the ODI tables. Players are in the rankings as soon as they complete a match. However, we only publish the top 100 players (at most), so it can take several matches for a player to break into that.