The 34-year-old six-time Ballon d'Or winner has a left hamstring problem and a painful knee. Messi had gone off at half-time of PSG's 2-1 Ligue 1 victory over Lille last Friday but coach Mauricio Pochettino had said he expected him to be fit for the Leizig match. However, he missed training on Monday and on Tuesday the club confirmed he would not after all be fit.PSG's statement said the four-time Champions League winner was suffering from "a pain in his hamstring in his left thigh and a painful knee due to bruising." Messi may also be a doubt for Saturday's Ligue 1 clash between table-toppers PSG and strugglers Bordeaux. He is due to then join up with his national squad for two World Cup qualifiers against Uruguay and Brazil.Wednesday's game will be the third match that Messi has missed this season due to injury, having sat out two Ligue 1 matches at the end of September. Messi has made a low-key start to his spell at the French giants since arriving from Barcelona in August.However, he produced one of his better performances in the 3-2 win over Leipzig a fortnight ago in Paris, scoring a double including the winner from the penalty spot. He said when he ended almost two decades at Barcelona a major reason for joining PSG was to win a fifth Champions League trophy.  PSG will also be missing influential midfielder Marco Verratti -- who has a hip injury -- but welcome back French World Cup winner Kylian Mbappe into the squad after missing the game with Lille. PSG top their Champions League group after three matches with seven points. Last season's beaten finalists Manchester City are a point behind whilst Leipzig are yet to get off the mark after three defeats.