The England hopeful rose for a ball in the air, but when he came back down to his feet, the knee buckled and Rodriguez immediately went to ground in a lot of pain.
Rodriguez was battling for a spot in the England team ahead of the summer’s World Cup. To make matters even worse, England manager Roy Hodgson was in the stands watching the match.
The scoreline flattered City on this day, as the Saints came to the Etihad with attacking intentions and even bossed the game to an extent in the first half.
But the title challengers rose to the occasion knocking in two goals in stoppage time before the half was up.
City now are within one point of Liverpool with a game in hand.