If klopp does want to rest a few players for the club world cup, if fifa ends up allowing it, i think the African players, mane, keita, salah, and the South American players Allisson, Firmino and Fabinho will all say to klopp they want to play in it, but klopp does have the final say though. It is bigger for Asian, African, South American players this competition. Its not prestigious in Europe though so some of the European players might not mind not taking part, or they might mind. Just a thought.