What does it mean when they bring in the ringer?

Answer 1

This means that this person is just right, or fits the bill, is the best for the job.

Perhaps but in sports a ringer is someone playing for a regular legal player but is not in fact a member of the team. Usually a superior player or a professional playing in amateur leagues, they are illegal and teams using them must forfeit the game if caught.

A ringer is also someone who is a double for another person, an exact duplicate, coming originally from a horse substituted for another of similar appearance in order to defraud the bookies (called a ringer).

Answer 2

The phrase "bringing in the ringer" is most commonly used when referring to a sporting competition where one team inserts a participant who has such an advantage over the opposing team that the outcome is considered assured. This advantage may be the result of legitimate ability, or it may be the result of illegal or unethical means. In other words, a "ringer" may be able to dictate the outcome of a competition because they are simply better than all other competitors, or because they have broken the rules for their own benefit. So, the use of a "ringer" may be characterized--depending on the situation--as the justifiable strategic use of a superior talent, or it may be seen as an unfair tactic that achieves advantage through deceit or actions that fall outside of the accepted rules. It should also be noted that references to a "ringer" are not limited to sports alone. For example, a group of attorney's may "bring in the ringer" (an exceptionally talented lawyer) to ensure a successful judgement. Thus, any endeavor can have a "ringer". What distinguishes the implication of its usage is the manner in which the "ringer" has acquired the advantages that compel this title.