After an 18-year tenure in professional soccer, Sergio Agüero is retiring from the game. The 33-year-old Argentine striker is calling it quits due to heart complications. Agüero had joined Barcelona last summer on a free transfer after a ten-year spell with Manchester City. Although Agüero still had a few more years left in him, there’s no doubt he had an illustrious career and he’s retiring in style. Earlier this month, Agüero was diagnosed with cardiac arrhythmia. After experiencing chest pains during a match against Alavés, Agüero was substituted out and taken to the hospital. He would be r…