This can he or can't he play in the CL debate is amusing.

nevermind, here are the actual rules:
http://www.uefa.com/MultimediaFiles.../Regulations/02/35/87/89/2358789_DOWNLOAD.pdf
42.07 As a rule, a player may not play in a UEFA club competition (i.e. UEFA Champions
League and UEFA Europa League, but not UEFA Super Cup) for more than one
club in the course of the same season. Exceptionally, however, a player who has
been fielded in the first, second, third qualifying round or the play-offs of the
UEFA Champions League or UEFA Europa League is entitled to play in the UEFA
Champions League or UEFA Europa League for another club as from the group
stage.
League and UEFA Europa League, but not UEFA Super Cup) for more than one
club in the course of the same season. Exceptionally, however, a player who has
been fielded in the first, second, third qualifying round or the play-offs of the
UEFA Champions League or UEFA Europa League is entitled to play in the UEFA
Champions League or UEFA Europa League for another club as from the group
stage.
