A 26-year-old female soccer player presents to your clinic with a 1-day history of severe left knee pain and swelling following a sudden change in direction during a match. She reports hearing a “pop” at the time of injury and has since been unable to bear weight on the affected leg. On physical examination, you note marked swelling and tenderness over the anterior aspect of the left knee. A positive Lachman test and negative posterior drawer test are also observed. Based on these findings, you suspect a specific knee ligament injury. Given the physical examination findings, which knee ligament injury is most likely, and what is the appropriate next step in management for this patient?