When the Champions League returns from its winter hiatus for the knockout stage starting on Feb. 12, most of the familiar teams will be present: Barcelona and Real Madrid, the Manchester sides City and United, Juventus and Bayern Munich. But a significant number of stars will be absent, particularly from a few teams hoping to win their first Champions League title. The latest name added to the list is Neymar, the Brazilian star whose foot injury could keep him out until late March, meaning he would miss both legs of Paris St.-Germain’s Round of 16 tie against Manchester United, according to multiple news media accounts, including the French sports newspaper L’Equipe. Another title hopeful, England’s Tottenham Hotspur, already is missing its two best attackers, and Atlético Madrid lost a key defender on Monday. Paris St.-Germain had previously acknowledged doubts that Neymar would be ready for the first leg against United on Feb. 12. Neymar had left the field in tears with the injury, reportedly a fractured metatarsal in his right foot, during a French Cup game last week. “It will be very difficult” for Neymar to return in time to face Manchester United, P.S.G.’s German coach, Thomas Tuchel, said after…