Lionel Messi has been ruled out of Paris Saint-Germain's Ligue 1 match at Metz on Wednesday night due to an injury to his left knee. PSG announced on Tuesday that the Argentine forward underwent an MRI scan which confirmed the signs of bone contusion. Another scan will be performed in 48 hours, the club said in a statement. An injury to Messi will be a huge concern for the Parisian club, who take on Manchester City in the Champions League next Tuesday. It has been a tough few days for the superstar attacker, who was substituted by manager Mauricio Pochettino during the league match against Lyon on Sunday. Messi was unhappy with the decision at the Parc des Princes, rejecting Pochettino's hand as he walked past his coach towards the PSG bench. Pochettino defended his decision to replace the 34-year-old with Achraf Hakimi for the final quarter-of-an-hour with the score at 1-1 as the star player started began to fade. A stoppage-time header from substitute Mauro Icardi sealed a 2-1 comeback win for PSG. Messi has yet to score since his move to France from Spanish giants Barcelona.