backup man

[Carollacob]

someone who takes the place of another (as when things get dangerous or difficult)

[DebrahCom]

A backup man is a person who provides assistance, support or takes the position of another person in case they are unable, unavailable or incapable of performing their duties or roles. This term can be used in various contexts such as in a work environment, emergency situations, sports, entertainment industry or in any scenario where a backup or second option is needed.