Viviano has been brought in as a back-up option to first-choice goalkeeper Wojciech Szczesny.
The absence alert provides a back up in contact in case of emergencies.
It never hurts to ask for a second one just in case you need a back up.
This way, you have a back up in case you make a mistake.
Nail down who will care for your pets and have a back up just in case.
Have a back up plan in the event of rain, and have suitable clothing to match.
"Martin hasn't come in as a replacement for Rio Ferdinand, he's come in as a back-up right-back for Glen Johnson," Gerrard told BBC Sport.
Kanaan, racing in a back-up car, ultimately finished in third place, behind Oriol Servia.
For Johnson, the win in a back-up car after wrecking in practice sends a message to the rest of the field that his team is as strong as ever as it begins defense of his title.
"This time I'm looking forward to being in a back-up role and will look to support Almunia," Lehmann added.
Spaniard Carmen Jorda has become the second woman to join a Formula 1 team in a back-up role after signing up with Lotus as development driver.
