What does it mean when they bring in the ringer?

When someone is referred to as "the ringer," it means they are a highly skilled or experienced individual brought in to participate in a competition or event in order to increase the chances of winning. This term is often used in informal or colloquial settings to describe someone who is expected to outperform others due to their exceptional abilities. The ringer is typically seen as the strongest competitor and is relied upon to achieve success for their team or group.