Identify the Injury: While at a flag football game, an athlete tries to grab the flags off of another player and as she does so her finger gets caught on the flags. The athlete says that her finger was stuck in the flags and was pulled in a weird way and she says that her distal 4th phalanx has a lot of pain. You notice swelling over the distal 4th phalanx and that the athlete is unable to flex the DIP joint in that finger. This athlete may be suffering from which injury?